persistence helper encoder

Persistence encoder hepls to consume messages from a zmq baked file
remove persistence related code
update README about 0.2.0 release
enhance device code
returns -1 with EAGAIN when mandatory is set and pipe is full
Merge pull request #29 from miniway/master

returns -1 with EAGAIN when mandatory is set and pipe is full
handle ConcurrentModification Exception
Merge pull request #30 from miniway/master

handle ConcurrentModification Exception
ZMsg.send returns boolean value
Merge pull request #31 from miniway/master

ZMsg.send returns boolean value
jdk epoll bug workaround
fix POLLOUT polling causes InvalidArgumentException
Issue#34 inproc connect should raise ZMQException
Merge pull request #35 from miniway/master

Issue #32 jdk epoll bug workaround and