Leverage opcode mysql cookbook

Forked from #18 

Awhile ago, I spent some time getting the right things into the official opscode mysql cookbook so that mysql analogs like percona or mariadb could leverage that cookbook and reduce duplication:
http://tickets.opscode.com/browse/COOK-1236

It seems that now the mysql cookbook is starting to add percona-related stuff, so this is the kick in the butt that I needed to get this started :)
https://github.com/opscode-cookbooks/mysql/blob/master/recipes/percona_repo.rb

Going to see if I can make progress on this soon, if no one has any concerns. I might ask clarification questions as I come across things and am wondering whether simplications might suffice. (I can only assume that this will be a major version bump..?)

Cheers!