Updated codemirror to v4.12.

Did a lot of cleanup to limit the size of the plugin.
I kept the emmet plugin.

applications/admin/static/codemirror/addon/comment/comment.js

@@ -1,3 +1,6 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
 (function(mod) {
   if (typeof exports == "object" && typeof module == "object") // CommonJS
     mod(require("../../lib/codemirror"));
@@ -106,7 +109,7 @@
   CodeMirror.defineExtension("uncomment", function(from, to, options) {
     if (!options) options = noOptions;
     var self = this, mode = self.getModeAt(from);
-    var end = Math.min(to.line, self.lastLine()), start = Math.min(from.line, end);
+    var end = Math.min(to.ch != 0 || to.line == from.line ? to.line : to.line - 1, self.lastLine()), start = Math.min(from.line, end);
 
     // Try finding line comments
     var lineString = options.lineComment || mode.lineComment, lines = [];
@@ -150,6 +153,17 @@
         !/comment/.test(self.getTokenTypeAt(Pos(end, close + 1))))
       return false;
 
+    // Avoid killing block comments completely outside the selection.
+    // Positions of the last startString before the start of the selection, and the first endString after it.
+    var lastStart = startLine.lastIndexOf(startString, from.ch);
+    var firstEnd = lastStart == -1 ? -1 : startLine.slice(0, from.ch).indexOf(endString, lastStart + startString.length);
+    if (lastStart != -1 && firstEnd != -1 && firstEnd + endString.length != from.ch) return false;
+    // Positions of the first endString after the end of the selection, and the last startString before it.
+    firstEnd = endLine.indexOf(endString, to.ch);
+    var almostLastStart = endLine.slice(to.ch).lastIndexOf(startString, firstEnd - to.ch);
+    lastStart = (firstEnd == -1 || almostLastStart == -1) ? -1 : to.ch + almostLastStart;
+    if (firstEnd != -1 && lastStart != -1 && lastStart != to.ch) return false;
+
     self.operation(function() {
       self.replaceRange("", Pos(end, close - (pad && endLine.slice(close - pad.length, close) == pad ? pad.length : 0)),
                         Pos(end, close + endString.length));

applications/admin/static/codemirror/addon/comment/continuecomment.js

@@ -0,0 +1,85 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+(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) {
+  var modes = ["clike", "css", "javascript"];
+
+  for (var i = 0; i < modes.length; ++i)
+    CodeMirror.extendMode(modes[i], {blockCommentContinue: " * "});
+
+  function continueComment(cm) {
+    if (cm.getOption("disableInput")) return CodeMirror.Pass;
+    var ranges = cm.listSelections(), mode, inserts = [];
+    for (var i = 0; i < ranges.length; i++) {
+      var pos = ranges[i].head, token = cm.getTokenAt(pos);
+      if (token.type != "comment") return CodeMirror.Pass;
+      var modeHere = CodeMirror.innerMode(cm.getMode(), token.state).mode;
+      if (!mode) mode = modeHere;
+      else if (mode != modeHere) return CodeMirror.Pass;
+
+      var insert = null;
+      if (mode.blockCommentStart && mode.blockCommentContinue) {
+        var end = token.string.indexOf(mode.blockCommentEnd);
+        var full = cm.getRange(CodeMirror.Pos(pos.line, 0), CodeMirror.Pos(pos.line, token.end)), found;
+        if (end != -1 && end == token.string.length - mode.blockCommentEnd.length && pos.ch >= end) {
+          // Comment ended, don't continue it
+        } else if (token.string.indexOf(mode.blockCommentStart) == 0) {
+          insert = full.slice(0, token.start);
+          if (!/^\s*$/.test(insert)) {
+            insert = "";
+            for (var j = 0; j < token.start; ++j) insert += " ";
+          }
+        } else if ((found = full.indexOf(mode.blockCommentContinue)) != -1 &&
+                   found + mode.blockCommentContinue.length > token.start &&
+                   /^\s*$/.test(full.slice(0, found))) {
+          insert = full.slice(0, found);
+        }
+        if (insert != null) insert += mode.blockCommentContinue;
+      }
+      if (insert == null && mode.lineComment && continueLineCommentEnabled(cm)) {
+        var line = cm.getLine(pos.line), found = line.indexOf(mode.lineComment);
+        if (found > -1) {
+          insert = line.slice(0, found);
+          if (/\S/.test(insert)) insert = null;
+          else insert += mode.lineComment + line.slice(found + mode.lineComment.length).match(/^\s*/)[0];
+        }
+      }
+      if (insert == null) return CodeMirror.Pass;
+      inserts[i] = "\n" + insert;
+    }
+
+    cm.operation(function() {
+      for (var i = ranges.length - 1; i >= 0; i--)
+        cm.replaceRange(inserts[i], ranges[i].from(), ranges[i].to(), "+insert");
+    });
+  }
+
+  function continueLineCommentEnabled(cm) {
+    var opt = cm.getOption("continueComments");
+    if (opt && typeof opt == "object")
+      return opt.continueLineComment !== false;
+    return true;
+  }
+
+  CodeMirror.defineOption("continueComments", null, function(cm, val, prev) {
+    if (prev && prev != CodeMirror.Init)
+      cm.removeKeyMap("continueComment");
+    if (val) {
+      var key = "Enter";
+      if (typeof val == "string")
+        key = val;
+      else if (typeof val == "object" && val.key)
+        key = val.key;
+      var map = {name: "continueComment"};
+      map[key] = continueComment;
+      cm.addKeyMap(map);
+    }
+  });
+});