Solution: replace all occurrences with `zmq_ctx_term`

Solution: update to 2016

Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.

Solution: specify these grants in the header of each source file.

Solution: update for 2015

Fixes #1320

- 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