Prepare 2.0.0 release.
Merge pull request #325 from apenney/200-final-release

Prepare 2.0.0 release.
Fix description for PE3.1

In PE3.1 it parses the comment #Deprecated at the top of the parameters
as if it's the class description.  Move this so PE3.1 doesn't falsely
claim mysql::server is now deprecated.
Merge pull request #326 from apenney/nigel-fix

Fix description for PE3.1
support mariadb

let's start by removing the 16 char username limit