Complete mysql::galera rewrite

This commit represents almost a complete
module rewrite for gelera.

- Adds unit tests and unit test dependencies
- depends on the puppetlabs mysql module and borrows
as much functionality as possible from this module
Merge pull request #2 from bodepd/master

Pull in Module Rewrite
Merge pull request #2 from danehans/master

A Complete Rewrite of the Galera Module