[fix] Fix shortcut enabling flag for 'ESC'

This is an adjustment to #2891.

settings.json.template

@@ -80,6 +80,7 @@
     "cmdShift2" : true, /* shows a gritter popup showing a line author */
     "delete"    : true,
     "return"    : true,
+    "esc"       : true, /* in mozilla versions 14-19 avoid reconnecting pad */
     "cmdS"      : true, /* save a revision */
     "tab"       : true, /* indent */
     "cmdZ"      : true, /* undo/redo */

src/node/utils/Settings.js

@@ -111,6 +111,7 @@ exports.padShortcutEnabled = {
   "delete" : true,
   "cmdShift2" : true,
   "return" : true,
+  "esc" : true,
   "cmdS" : true,
   "tab" : true,
   "cmdZ" : true,

src/static/js/ace2_inner.js

@@ -3847,7 +3847,7 @@ function Ace2Inner(){
           }, 0);
           specialHandled = true;
         }
-        if ((!specialHandled) && isTypeForSpecialKey && keyCode == 27 && padShortcutEnabled.cmdS)
+        if ((!specialHandled) && isTypeForSpecialKey && keyCode == 27 && padShortcutEnabled.esc)
         {
           // prevent esc key;
           // in mozilla versions 14-19 avoid reconnecting pad.