UI: Make repository menu divide header and content

This is more inline with way GitHub looks like and feels much more natural and
in style with rest of the interface.

templates/repo/wiki/new.tmpl

@@ -1,8 +1,8 @@
 {{template "base/head" .}}
 <div class="repository wiki new">
-	{{template "repo/header" .}}
+  {{template "repo/header" .}}
+  {{template "repo/sidebar" .}}
   <div class="ui container">
-    {{template "repo/sidebar" .}}
     {{template "base/alert" .}}
     <div class="ui header">
       {{.i18n.Tr "repo.wiki.new_page"}}

templates/repo/wiki/pages.tmpl

@@ -1,8 +1,8 @@
 {{template "base/head" .}}
 <div class="repository wiki pages">
 	{{template "repo/header" .}}
+	{{template "repo/sidebar" .}}
   <div class="ui container">
-    {{template "repo/sidebar" .}}
     <div class="ui header">
     	{{.i18n.Tr "repo.wiki.pages"}}
     	<div class="ui right">

templates/repo/wiki/start.tmpl

@@ -1,8 +1,8 @@
 {{template "base/head" .}}
 <div class="repository wiki start">
 	{{template "repo/header" .}}
+	{{template "repo/sidebar" .}}
   <div class="ui container">
-    {{template "repo/sidebar" .}}
     <div class="ui center segment">
     	<span class="mega-octicon octicon-book"></span>
     	<h2>{{.i18n.Tr "repo.wiki.welcome"}}</h2>

templates/repo/wiki/view.tmpl

@@ -1,8 +1,8 @@
 {{template "base/head" .}}
 <div class="repository wiki view">
 	{{template "repo/header" .}}
+	{{template "repo/sidebar" .}}
   <div class="ui container">
-    {{template "repo/sidebar" .}}
     <div class="ui grid">
       <div class="ui ten wide column">
         <div class="choose page">