Update Version to include revision information.

I also changed the SDLVersion Storable instance to use Applicative
instead of Monad and to use a macro instead of hardcoding 1 for
alignment.

This is where I found the alignment macro -
http://stackoverflow.com/a/8354582/383958. I've used it before and it
seems to work, though I don't really understand it.
Merge pull request #1 from joelburget/master

Update Version to include revision information.