[Vala] Patch for cascading member access.

[Christian Johnson <_c_ mail com>]

After exploring a few rabbit holes I have come up with a patch for cascading
member access. I posted it on Bugzilla:
https://bugzilla.gnome.org/show_bug.cgi?id=686562#c2 but since it was
discussed on the mailing list as well I though I would post here too.

You can also find it on my gist: https://gist.github.com/RedHatter/7881160

So what's the review process?