Merge pull request #798 from hintjens/master

Added binary send/recv to zsock
Merge pull request #800 from hintjens/master

Problem: zsock_bsend/brecv assume 64-bit platform
Merge pull request #801 from hintjens/master

Adding zsys support for pipe creation
Merge pull request #802 from hintjens/master

Removed zring, fixed memory leaks