Merge pull request #9 from zTrix/support_half_shutdown

Support half open connection to ensure fd release as soon as tcp closed

Disable connection creation on client side.

Fix current map read and write bug.

Fix current map read and write bug.

Implement SetTimeout for InboundConnection.

Fix tunnel pool manager bug; Update peerID exchange method.

Add version when build; Remove debug info from docker image.

Add release publisher.