fix #45 remove const/mutable cast operators from message
resolve #38 Support parsing czmq binding specs

For tcp endpoints
Update socket::bind documentation
Remove errant '=='
Merge remote-tracking branch 'upstream/master'

Conflicts:
	test/socket/main.cpp
Merge pull request #51 from rodgert/master

resolve #38 Support parsing czmq binding specs

PR has been pending a while, merge on...