Add pmg on and update to cuttent ZMQ minor version.
Up to ZMQ 4.0.1.
Update ZMQ version, previous working strange.
Updated to 4.0.4
Updated vsn to 4.0
Added support for ctx_get/2 and ctx_set/3
Support max_sockets when creating context
(Bad, hard-coded) support for libsodium on Linux
Added support for Curve security
Added test for curve when sockets in active mode
Added erlzmq:z85_decode/1