more updates on the extension API

--HG--
branch : trunk
diff --git a/jinja2/parser.py b/jinja2/parser.py
index 91a848b..427cb05 100644
--- a/jinja2/parser.py
+++ b/jinja2/parser.py
@@ -42,13 +42,20 @@
                                             'rparen') or \
                self.stream.current.test('name:in')
 
-    def ignore_colon(self):
+    def skip_colon(self):
         """If there is a colon, skip it and return `True`, else `False`."""
         if self.stream.current.type is 'colon':
             self.stream.next()
             return True
         return False
 
+    def skip_comma(self):
+        """If there is a comma, skip it and return `True`, else `False`."""
+        if self.stream.current.type is 'comma':
+            self.stream.next()
+            return True
+        return False
+
     def free_identifier(self, lineno=None):
         """Return a new free identifier as :class:`~jinja2.nodes.InternalName`."""
         self._last_identifier += 1
@@ -100,7 +107,7 @@
         can be set to `True` and the end token is removed.
         """
         # the first token may be a colon for python compatibility
-        self.ignore_colon()
+        self.skip_colon()
 
         # in the future it would be possible to add whole code sections
         # by adding some sort of end of statement token and parsing those here.