Initial merge of vim-haxe-syntax into vaxe

Hi Marc,

I've moved a few things around to make this repo easier to use as a subtree.  Subtrees make it possible to use shared code inside vundle, etc.  Basically, the haxe.vim syntax file is now in the root, and the subtree command will clone this repo to ./syntax

I've also added hxml syntax coloring here.

Finally, I removed the errorformat specification here, I'd rather manage this outside the syntax file.  Is that ok?