Refactor MySQL bindings and client packages.

The current MySQL module is hard to modify, test, and drop in
replacement components to.  This work starts out by refactoring
the bindings support in MySQL to a completely seperate bindings
class in order to reduce the amount of parameters in the main
class for a feature that is infrequently used.

In addition to this start the movement of client configuration
and packages to the mysql::client::* namespace.
Merge pull request #232 from apenney/refactor-round-1

Refactor MySQL bindings and client packages.
Fix puppet 2.6 compatibility
Merge pull request #235 from ekohl/puppet-2.6-compat

Fix puppet 2.6 compatibility
Update changelog.
Merge pull request #236 from apenney/changelog

Update changelog.
Add compatibility classes to handle the backwards incompatible changes.
Fix this so we don't list dates or versions yet.
Merge pull request #238 from apenney/changelog-fix

Fix this so we don't list dates or versions yet.
Merge pull request #237 from apenney/backwards-compat

Add compatibility classes to handle the backwards incompatible changes.
Add environment variable for .my.cnf and specs
Merge pull request #243 from hunner/fix_sql

Add environment variable for .my.cnf and specs