* refactored ZChannel/ZMQ.Socket/ZAbstractClient API -- made it cleaner and simpler.
* refactored pooling abstraction -- created generic multithreaded/non-blocking pooling framework.
* refactored tests -- now they look much cleaner.
* re-committing ZBaseSocketFactory -- didn't succeded from first try (o_O ...).
* +ZException.
* did a refactoring.
* optimized code in ZWorker and ZRouter.
* -Utils.
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/main/java/org/zeromq/messaging/ZConstants.java
* ZRouter --> ZProxy. Renamed package as well.
* +just_works test on ZRouter.
* +multithreaded support on ZFactory.
* +exception_code in ZException.
* minor update.