WIP: Implement ES6 Spread-calls

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index b4da5326d661379e389b12f13abc3b4337196642..536c7740488e6510cea6cccdd95d272c456828b0 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -180,7 +180,10 @@ var kMessages = {
   super_constructor_call:        ["A 'super' constructor call may only appear as the first statement of a function, and its arguments may not access 'this'. Other forms are not yet supported."],
   duplicate_proto:               ["Duplicate __proto__ fields are not allowed in object literals"],
   param_after_rest:              ["Rest parameter must be last formal parameter"],
-  constructor_noncallable:       ["Class constructors cannot be invoked without 'new'"]
+  constructor_noncallable:       ["Class constructors cannot be invoked without 'new'"],
+
+  spreadcall_intrinsic:          ["Spread arguments may not be used to invoke intrinsics"],
+  spreadcall_construct:          ["Spread arguments may not be used to call constructors"]
 };