removing extensions from CoffeeScript

src/grammar.coffee

@@ -100,7 +100,6 @@ grammar: {
     o "Splat"
     o "Existence"
     o "Comment"
-    o "Extension"
   ]
 
   # A an indented block of expressions. Note that the [Rewriter](rewriter.html)
@@ -396,12 +395,6 @@ grammar: {
     o "( Line )",                               -> new ParentheticalNode $2
   ]
 
-  # A language extension to CoffeeScript from the outside. We simply pass
-  # it through unaltered.
-  Extension: [
-    o "EXTENSION"
-  ]
-
   # The condition portion of a while loop.
   WhileSource: [
     o "WHILE Expression",                       -> new WhileNode $2