Moved vendored js/css into public/vendor and documented sources (#1484) (#2241)

* Cleaning up public/ and documenting js/css libs.

This commit mostly addresses #1484 by moving vendor'ed plugins into a
vendor/ directory and documenting their upstream source and license in
vendor/librejs.html.

This also proves gitea is using only open source js/css libraries which
helps toward reaching #1524.

* Removing unused css file.

The version of this file in use is located at:
  vendor/plugins/highlight/github.css

* Cleaned up librejs.html and added javascript header

A SafeJS function was added to templates/helper.go to allow keeping
comments inside of javascript.

A javascript comment was added in the header of templates/base/head.tmpl
to mark all non-inline source as free.

The librejs.html file was updated to meet the current librejs spec. I
have now verified that the librejs plugin detects most of the scripts
included in gitea and suspect the non-free detections are the result of
a bug in the plugin. I believe this commit is enough to meet the C0.0
requirement of #1534.

* Updating SafeJS function per lint suggestion

* Added VERSIONS file, per request

public/vendor/plugins/codemirror/mode/stex/stex.js

@@ -0,0 +1,251 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+/*
+ * Author: Constantin Jucovschi (c.jucovschi@jacobs-university.de)
+ * Licence: MIT
+ */
+
+(function(mod) {
+  if (typeof exports == "object" && typeof module == "object") // CommonJS
+    mod(require("../../lib/codemirror"));
+  else if (typeof define == "function" && define.amd) // AMD
+    define(["../../lib/codemirror"], mod);
+  else // Plain browser env
+    mod(CodeMirror);
+})(function(CodeMirror) {
+  "use strict";
+
+  CodeMirror.defineMode("stex", function() {
+    "use strict";
+
+    function pushCommand(state, command) {
+      state.cmdState.push(command);
+    }
+
+    function peekCommand(state) {
+      if (state.cmdState.length > 0) {
+        return state.cmdState[state.cmdState.length - 1];
+      } else {
+        return null;
+      }
+    }
+
+    function popCommand(state) {
+      var plug = state.cmdState.pop();
+      if (plug) {
+        plug.closeBracket();
+      }
+    }
+
+    // returns the non-default plugin closest to the end of the list
+    function getMostPowerful(state) {
+      var context = state.cmdState;
+      for (var i = context.length - 1; i >= 0; i--) {
+        var plug = context[i];
+        if (plug.name == "DEFAULT") {
+          continue;
+        }
+        return plug;
+      }
+      return { styleIdentifier: function() { return null; } };
+    }
+
+    function addPluginPattern(pluginName, cmdStyle, styles) {
+      return function () {
+        this.name = pluginName;
+        this.bracketNo = 0;
+        this.style = cmdStyle;
+        this.styles = styles;
+        this.argument = null;   // \begin and \end have arguments that follow. These are stored in the plugin
+
+        this.styleIdentifier = function() {
+          return this.styles[this.bracketNo - 1] || null;
+        };
+        this.openBracket = function() {
+          this.bracketNo++;
+          return "bracket";
+        };
+        this.closeBracket = function() {};
+      };
+    }
+
+    var plugins = {};
+
+    plugins["importmodule"] = addPluginPattern("importmodule", "tag", ["string", "builtin"]);
+    plugins["documentclass"] = addPluginPattern("documentclass", "tag", ["", "atom"]);
+    plugins["usepackage"] = addPluginPattern("usepackage", "tag", ["atom"]);
+    plugins["begin"] = addPluginPattern("begin", "tag", ["atom"]);
+    plugins["end"] = addPluginPattern("end", "tag", ["atom"]);
+
+    plugins["DEFAULT"] = function () {
+      this.name = "DEFAULT";
+      this.style = "tag";
+
+      this.styleIdentifier = this.openBracket = this.closeBracket = function() {};
+    };
+
+    function setState(state, f) {
+      state.f = f;
+    }
+
+    // called when in a normal (no environment) context
+    function normal(source, state) {
+      var plug;
+      // Do we look like '\command' ?  If so, attempt to apply the plugin 'command'
+      if (source.match(/^\\[a-zA-Z@]+/)) {
+        var cmdName = source.current().slice(1);
+        plug = plugins[cmdName] || plugins["DEFAULT"];
+        plug = new plug();
+        pushCommand(state, plug);
+        setState(state, beginParams);
+        return plug.style;
+      }
+
+      // escape characters
+      if (source.match(/^\\[$&%#{}_]/)) {
+        return "tag";
+      }
+
+      // white space control characters
+      if (source.match(/^\\[,;!\/\\]/)) {
+        return "tag";
+      }
+
+      // find if we're starting various math modes
+      if (source.match("\\[")) {
+        setState(state, function(source, state){ return inMathMode(source, state, "\\]"); });
+        return "keyword";
+      }
+      if (source.match("$$")) {
+        setState(state, function(source, state){ return inMathMode(source, state, "$$"); });
+        return "keyword";
+      }
+      if (source.match("$")) {
+        setState(state, function(source, state){ return inMathMode(source, state, "$"); });
+        return "keyword";
+      }
+
+      var ch = source.next();
+      if (ch == "%") {
+        source.skipToEnd();
+        return "comment";
+      } else if (ch == '}' || ch == ']') {
+        plug = peekCommand(state);
+        if (plug) {
+          plug.closeBracket(ch);
+          setState(state, beginParams);
+        } else {
+          return "error";
+        }
+        return "bracket";
+      } else if (ch == '{' || ch == '[') {
+        plug = plugins["DEFAULT"];
+        plug = new plug();
+        pushCommand(state, plug);
+        return "bracket";
+      } else if (/\d/.test(ch)) {
+        source.eatWhile(/[\w.%]/);
+        return "atom";
+      } else {
+        source.eatWhile(/[\w\-_]/);
+        plug = getMostPowerful(state);
+        if (plug.name == 'begin') {
+          plug.argument = source.current();
+        }
+        return plug.styleIdentifier();
+      }
+    }
+
+    function inMathMode(source, state, endModeSeq) {
+      if (source.eatSpace()) {
+        return null;
+      }
+      if (source.match(endModeSeq)) {
+        setState(state, normal);
+        return "keyword";
+      }
+      if (source.match(/^\\[a-zA-Z@]+/)) {
+        return "tag";
+      }
+      if (source.match(/^[a-zA-Z]+/)) {
+        return "variable-2";
+      }
+      // escape characters
+      if (source.match(/^\\[$&%#{}_]/)) {
+        return "tag";
+      }
+      // white space control characters
+      if (source.match(/^\\[,;!\/]/)) {
+        return "tag";
+      }
+      // special math-mode characters
+      if (source.match(/^[\^_&]/)) {
+        return "tag";
+      }
+      // non-special characters
+      if (source.match(/^[+\-<>|=,\/@!*:;'"`~#?]/)) {
+        return null;
+      }
+      if (source.match(/^(\d+\.\d*|\d*\.\d+|\d+)/)) {
+        return "number";
+      }
+      var ch = source.next();
+      if (ch == "{" || ch == "}" || ch == "[" || ch == "]" || ch == "(" || ch == ")") {
+        return "bracket";
+      }
+
+      if (ch == "%") {
+        source.skipToEnd();
+        return "comment";
+      }
+      return "error";
+    }
+
+    function beginParams(source, state) {
+      var ch = source.peek(), lastPlug;
+      if (ch == '{' || ch == '[') {
+        lastPlug = peekCommand(state);
+        lastPlug.openBracket(ch);
+        source.eat(ch);
+        setState(state, normal);
+        return "bracket";
+      }
+      if (/[ \t\r]/.test(ch)) {
+        source.eat(ch);
+        return null;
+      }
+      setState(state, normal);
+      popCommand(state);
+
+      return normal(source, state);
+    }
+
+    return {
+      startState: function() {
+        return {
+          cmdState: [],
+          f: normal
+        };
+      },
+      copyState: function(s) {
+        return {
+          cmdState: s.cmdState.slice(),
+          f: s.f
+        };
+      },
+      token: function(stream, state) {
+        return state.f(stream, state);
+      },
+      blankLine: function(state) {
+        state.f = normal;
+        state.cmdState.length = 0;
+      },
+      lineComment: "%"
+    };
+  });
+
+  CodeMirror.defineMIME("text/x-stex", "stex");
+  CodeMirror.defineMIME("text/x-latex", "stex");
+
+});