add error event capture for socket

Change-Id: I6a91642431c3d4944e86f3f33895c97268ffe9fa
fix duplicated disconnect/error event bug

Change-Id: I51afb8da56a0bf2dc35a0beb16b6c0dc07a1e9fd
fix session.bind bug in backend server

Change-Id: I3bce5c5596441c56e75aff24536142989b1b1fd9
replace exec with spawn

Change-Id: I597f2b10c0c36e909b3ff2de1ffac3dd72e4bec6
upgrade to 0.3.10

Change-Id: I0a32a58e64087eaebf1f561174fa266076a882bc
clean code

Change-Id: I0e8e887c4bb8b392cc7bc8af2e0620405eae1d6b
Merge branch 'master' into 0.3.x-scheduler
merge from 0.3.x-scheduler

Change-Id: Ie5b04b8da8c80bea869f5b9769b1be3daf4b6987