feat: change template micro-syntax to new syntax

Old syntax:
- ng-repeat: #item in items;
- ng-repeat: #item; in: items;
- <template let-ng-repeat=“item” [in]=items>

New syntax:
- ng-repeat: var item in items;
- ng-repeat: var item; in items
- <template ng-repeat var-item [in]=items>


Notice that the var is now a standalone binding 
rather then an argument to ng-repeat. This will 
make the var bindings consistent with the rest of 
the system.

Closes #482

modules/change_detection/src/parser/lexer.js

@@ -62,6 +62,10 @@ export class Token {
     return (this.type == TOKEN_TYPE_KEYWORD);
   }
 
+  isKeywordVar():boolean {
+    return (this.type == TOKEN_TYPE_KEYWORD && this._strValue == "var");
+  }
+
   isKeywordNull():boolean {
     return (this.type == TOKEN_TYPE_KEYWORD && this._strValue == "null");
   }
@@ -469,6 +473,7 @@ var OPERATORS = SetWrapper.createFromList([
 
 
 var KEYWORDS = SetWrapper.createFromList([
+    'var',
     'null',
     'undefined',
     'true',