- used msleep (10) in most places instead of zmq_sleep (1)
- may cause failures on slower machines
- to change, modify SETTLE_TIME in testutil.h
- tested down to 1 msec on fast boxes

* Removed redundant Z85 code and include files from project
* Simplified use of headers in test cases (now they all just use testutil.hpp)
* Export zmq_z85_encode() and zmq_z85_decode() in API
* Added man pages for these two functions