Fix socket creation above sistem limits for all 'other' OS not covered by eventfd, windows or vms; enhanced test to create sockets up to a bigger limit to really test hitting the OS limit
issue #583 removing C++11 code.
Revert "Make FD_SETSIZE = ZMQ_MAX_SOCKETS_DFLT + 1 so there is room for the repear socket."

This reverts commit 0b92831b2a82c3bbc0e9371662c546b94915a3ea.
Reduce default maximum number of sockets by 1 so there is room for the reaper socket.
Fix signed/unsigned comparison
Fix signed/unsigned comparison
return error to caller on bind error
remove all asserts during critical section

the size of the critical section is reduced by only entering the critical
section right before the bind().
Added links to RFCs for socket patterns