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/runmode/runmode.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"));
@@ -57,6 +60,7 @@ CodeMirror.runMode = function(string, modespec, callback, options) {
   for (var i = 0, e = lines.length; i < e; ++i) {
     if (i) callback("\n");
     var stream = new CodeMirror.StringStream(lines[i]);
+    if (!stream.string && mode.blankLine) mode.blankLine(state);
     while (!stream.eol()) {
       var style = mode.token(stream, state);
       callback(stream.current(), style, i, stream.start, state);