Merge pull request #657 from hintjens/master

Build didn't work if libsodium wasn't installed
Support high water mark on inproc socket connect before bind.
Set hwm on connect socket before bind has happend to just that of connects hwm.
Merge branch 'master' of https://github.com/zeromq/libzmq into inproc_connect_before_bind
Merge pull request #658 from ricnewton/inproc_connect_before_bind

Support high water mark on inproc socket connect before bind.
Minor simplification to makefile
Fixed Z85 methods to be static and not pollute library