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/mode/htmlmixed/htmlmixed.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"), require("../xml/xml"), require("../javascript/javascript"), require("../css/css"));
@@ -27,6 +30,7 @@ CodeMirror.defineMode("htmlmixed", function(config, parserConfig) {
 
   function html(stream, state) {
     var tagName = state.htmlState.tagName;
+    if (tagName) tagName = tagName.toLowerCase();
     var style = htmlMode.token(stream, state.htmlState);
     if (tagName == "script" && /\btag\b/.test(style) && stream.current() == ">") {
       // Script block: mode to change to depends on type attribute
@@ -65,7 +69,7 @@ CodeMirror.defineMode("htmlmixed", function(config, parserConfig) {
     if (stream.match(/^<\/\s*script\s*>/i, false)) {
       state.token = html;
       state.localState = state.localMode = null;
-      return html(stream, state);
+      return null;
     }
     return maybeBackup(stream, /<\/\s*script\s*>/,
                        state.localMode.token(stream, state.localState));
@@ -74,7 +78,7 @@ CodeMirror.defineMode("htmlmixed", function(config, parserConfig) {
     if (stream.match(/^<\/\s*style\s*>/i, false)) {
       state.token = html;
       state.localState = state.localMode = null;
-      return html(stream, state);
+      return null;
     }
     return maybeBackup(stream, /<\/\s*style\s*>/,
                        cssMode.token(stream, state.localState));