Object::GetConstructor is wrong (test_ObjectGetConstructorName)

[zpao]

This might just be a difference in interpretations that spidermonkey has wrong, or we're doing something wrong in v8monkey, but we're pretty faily here. test_ObjectGetConstructorName is pretty clear here, so that should be good enough.

In combination with issue #86, we're not doing so well with function names :(

[zpao]

To add more...

c->ToObject()->GetConstructorName() returns Parent, when it should be Child

x->ToObject()->GetConstructorName() (that's the outer.inner one) crashes because JS_GetFunctionId returns null, which we aren't checking before passing that off to String::New

When "fixing" that so inner isn't anonymous, GetConstructorName returns inner (but expects outer.inner)

[zpao]

I committed 73b203d so we no longer crash trying to get the name of an anonymous function. We'll currently just return an empty string (not an empty string handle)