Notifications: mark as read/unread and pin (#629)

* Use relative URLs

* Notifications - Mark as read/unread

* Feature of pinning a notification

* On view issue, do not mark as read a pinned notification

public/less/_user.less

@@ -85,6 +85,16 @@
             margin-left: 7px;
         }
 
+        .buttons-panel {
+            button {
+                padding: 3px;
+            }
+
+            form {
+                display: inline-block;
+            }
+        }
+
         .octicon-issue-opened, .octicon-git-pull-request {
             color: #21ba45;
         }
@@ -94,5 +104,8 @@
         .octicon-git-merge {
             color: #a333c8;
         }
+        .octicon-pin {
+            color: #2185d0;
+        }
     }
 }