Update ACE Editor to version 1.2.9

The new ACE editor introduces full support for emojis (and, thereby, UTF-16 characters with high- and low-surrogates). Hence, we can remove our custom fix.

Further, this update will allow emojis to be used in pair programming sessions.

vendor/assets/javascripts/ace/mode-lisp.js

@@ -72,7 +72,7 @@ var LispHighlightRules = function() {
             next  : "start"
         }
     ]
-}
+};
 
 };
 
@@ -90,6 +90,7 @@ var LispHighlightRules = require("./lisp_highlight_rules").LispHighlightRules;
 
 var Mode = function() {
     this.HighlightRules = LispHighlightRules;
+    this.$behaviour = this.$defaultBehaviour;
 };
 oop.inherits(Mode, TextMode);