util: switch to killbill-commons for locker and db testing helper

Update to killbill-commons 0.2.1 and get rid of the util specific
GlobalLocker and MysqlTestingHelper.

This also fixes the tests with a local database (-Dcom.ning.billing.dbi.test.useLocalDb=true):
TestDefaultBlockingApi was creating a bad bundles table that would later on break subscriptions
tests.

Note that we needed to update all subprojects pom.xml as test-jars dependencies are not
transitive (see http://jira.codehaus.org/browse/MNG-1378).

Misc. changes:

* Update .idea files
* Add mysql as a defined group

Testing Done: ran all tests with the embedded DB and with my local DB.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>