Made it work with Pathogen/Vundle, added some functions

All I did, really, was make it compatible with plugins like Pathogen and Vundle. Putting the `wordpress.vim` file in the syntax folder is the way I did this.

I also added some functions that @dbernar1's [pull request](https://github.com/kloppster/Wordpress-Vim-Syntax/pull/1) adds.

Please accept so that I can start using this plugin. :wink: