Make colemak-evil installable via package.el

Add [required package.el cruft](http://marmalade-repo.org/doc-files/package.5.html). The next step of this is to add a [Melpa](http://melpa.milkbox.net/#/) recipe.

A few simple things have been added as part of this:

* A `Version` entry, which I've pinned to `1.0.0`
* I've updated the header comment to be more scannable
* I've added a dependency on `evil`
* I've added a line that `provide`s the package, so it can be `require`d in `emacs.d`