Merge pull request #656 from ricnewton/inproc_connect_before_bind

Allow inproc sockets to connect before bind
Build didn't work if libsodium wasn't installed
Merge pull request #657 from hintjens/master

Build didn't work if libsodium wasn't installed
Merge branch 'master' of https://github.com/zeromq/libzmq into inproc_connect_before_bind