Moved Synchronizer and related classes into a separate package.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1481149 13f79535-47bb-0310-9956-ffa450edef68
Added new SynchronizerSupport interface.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1481150 13f79535-47bb-0310-9956-ffa450edef68