Updated man pages
Merge pull request #656 from jossgray/msvc_build_fixes

msvc build fixes. explicit casts required.
Problem: zsocket_set_xxx dies miserably if you pass a zsock_t

Solution: catch this specific error and die less miserably.
Fixed #657 properly
Merge pull request #657 from hintjens/master

Catch common error of zsocket_set_xxx on zsock_t sockets
Removing workaround for ZMQ #1169 as the problem no longer hits
Problem: zhash public API was broken

Changing keys from 'const char *' to 'void *' broke existing applications,
and isn't necessary. The majority use case is for char keys, so the API
can show this. The marginal case is for void * keys, which zhash does
internally without modifying the API. Apps that use non-string keys will
have to cast their keys to 'const char *', which is fine (the alternative
is that all existing apps have to add a cast just to allow a few unusual
apps to not add one.)
Merge pull request #658 from hintjens/master

Removing workaround for ZMQ #1169 as the problem no longer hits
Problem: dropped & in last patch, causing segfault

Solution: run 'make check' before pushing commits :-)
Merge pull request #659 from hintjens/master

Problem: dropped & in last patch, causing segfault
zhash msvc build fixes