Removing old ECANTROUTE documentation

Revert null checks in the API

Adding more specific installation instructions

Minor cleanups

* Fixed use of ssize_t in zmq_msg_t class
* Corrected error after merge, old reference to inner_fctname (broke build)

Return EFAULT if required arguments are null

Renamed scatter/gather methods, cleaned up source

Remove inet_ntop

Compact the trie/mtrie node tables where possible, to reduce memory usag...

Drop subscription messages when reaching the SNDHWM rather than assertin...

Resolve addresses in the calling thread on connect.

Added zmq_msg_send/recv functions

Renamed zmq_getmsgopt to zmq_msg_get

Signed-off-by: Staffan Gimåker <staffan@spotify.com>

This matches the behaviour of zmq_setsockopt(ZMQ_SUBSCRIBE, ...), which also
silently drops subscription messages if the SNDHWM is reached.
Signed-off-by: Staffan Gimåker <staffan@spotify.com>

This allows us to actually report an error to the caller on resolve
failure, rather than asserting later on in the io thread.
Signed-off-by: Staffan Gimåker <staffan@spotify.com>

* Added zmq_msg_poke for orthogonality
* Added zmq_msg_more for simplicity
* Fixed up man pages and test program

Cleanups to man pages