fix for osx10.7 to define symbol ENONET
Merge pull request #85 from ishwor/master

fix for osx10.7 to define symbol ENONET as EHOSTDOWN
Merge pull request #87 from hintjens/master

Stopped using zsys_ file functions (was changed in CZMQ)
Merge pull request #88 from hintjens/master

Fixed autotools config
Removed zre_udp class, deprecated by CZMQ zbeacon