Cance ability, which feeds down into the transfer service, and feeds it back up to the action tracking service. Also, refactor of the replication service unit tests to do the transactions itself, which is needed to reliably test async actions
git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@21387 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
