Added a toString() method to the Registration class

git-svn-id: https://svn.apache.org/repos/asf/mina/mina/trunk@1428681 13f79535-47bb-0310-9956-ffa450edef68
Moved the setConnected() into the register callback, to make sure it's executed on one single thread

git-svn-id: https://svn.apache.org/repos/asf/mina/mina/trunk@1428682 13f79535-47bb-0310-9956-ffa450edef68