Grammar cleanup

[waldemarhorwat]

A stylistic nit:

Is there a reason the BindingPattern has the extra parameter void? The cleaner and simpler approach would seem to be to leave BindingPattern as is and introduce a new BindingPatternOrVoid production which expands to either BindingPattern or void, but I'm not sure if there is some future planned consideration that I'm overlooking. I originally created the notion of parameters on grammar productions to avoid duplicating a deep tree of productions, which doesn't apply here.

Also, where can I find the base grammar that this one is a difference of?

[rbuckton]

I believe this was addressed by #9 as well.