add support for C++ scoping of class members in member functions where _this_ is implicit
Mmm, what? Isn't it what I did, that is that it considers the current scope when there's nothing on the left? My second commit doesn't try to handle `this.foo()` (which would be nice, but few languages use `this`), but `foo()` inside a scope. The idea being that if it's inside `Foo::bar`, it has to be part of one of the scopes `Foo::bar`, `Foo`, or none; but e.g. not `Baz`, as it wouldn't be accessible without an explicit prefix (unless inherited somehow, but we don't have that yet anywhere).