[Vala] Emacs Mode and lambda indentation

[David Gomes <david elementaryos org>]

I don't know how to write Emacs modes, and vala-mode seems to have a
problem:

cubes.foreach (() => {

    });

It doesn't indent those well. Basically, instead of indenting with 4 spaces
(like it does on if's, for's and other stuff), vala-mode indents with 8
spaces on the content** and with 4 spaces on the closing line with "});".

Does anybody have any idea of how to fix this? Thank you very much :)