allow comments in equation, default token in equation

lib/ace/mode/latex_highlight_rules.js

@@ -47,6 +47,9 @@ var LatexHighlightRules = function() {
             next  : "equation"
         }],
         "equation" : [{
+            token : "comment",
+            regex : "%.*$"
+        },{
             token : "string",
             regex : "\\${1,2}",
             next  : "start"
@@ -54,8 +57,7 @@ var LatexHighlightRules = function() {
             token : "constant.character.escape",
             regex : "\\\\(?:[^a-zA-Z]|[a-zA-Z]+)"
         },{
-            token : "string",
-            regex : "."
+            defaultToken : "string"
         }]
 
     };