[Vala] editor syntax support

[pancake <pancake youterm com>]

What do you think about adding the vala.vim (and others for emacs, 
gedit..) syntax
highlighter scripts inside the vala repository? I think it will be 
better to keep
them tracked in a git repo than in a wiki.

Many other languages do it in this way (read acr, parrot, perl6, go, ..)

--pancake