Remove dependency on mysql recipe
Clean up version attributes

Rename mysql.version to percona.version to keep in our own namespace.
Use variable instead of hard-coded version in cluster recipe.
Update default version to 5.6
Fix odd package names on ubuntu trusty
Override mysql-chef_gem to skip installing mysql client libs
rubocop style fixes
add ubuntu 14.04 to test kitchen platforms
add contribution from @avit to the README
Merge pull request #135 from phlipper/mysql-dependency

drop dependency on opscode/mysql cookbook

closes #73
closes #116
closes #128