allowing quoted strings within object assignment, a in JS and JSON

Author: jashkenas

lib/coffee_script/grammar.y

@@ -121,6 +121,7 @@ rule
   # Assignment within an object literal.
   AssignObj:
     IDENTIFIER ":" Expression         { result = AssignNode.new(val[0], val[2], :object) }
+  | STRING ":" Expression             { result = AssignNode.new(val[0], val[2], :object) }
   | Comment                           { result = val[0] }
   ;