fix divide by zero in zmq::lb_t::sendpipe

This is based on https://github.com/zeromq/zeromq3-x/pull/116/files

Make OS Xframwork build optional

* Fix possible clock_t crash on iOS 9.3.2 and 9.3.5 + macOS < 10.12

* No need to read return value

* Problem: zmq_z85_decode does not validate its input
Solution: added checks for invalid characters and overflows

* Added tests, added further check for range overflow, removed (multiple) calls to strlen

* Problem: gcc fails to build
Solution: added missing include directive

* Added VS2015 test_utils_z85 project

* Fixed indentation and copyright notice

* Resolved garbage from merge

* Revert "Added VS2015 test_utils_z85 project"

This reverts commit c58b3c664c144326e77135aa1184b6f0dee11143.

* Problem: test calls zmq_z85_decode with a NULL dest
Solution: call zmq_z85_decode with a properly sized buffer

* Problem: tests for zmq_z85_* scattered over two files
Solution: merged files

* Removed reference to removed test file from CMakeLists.txt

* Problem: Missing include directive to stdint.h
Solution: Added include directive

* Define __STDC_LIMIT_MACROS before including stdint.h

* Problem: Wrong variable is checked for invalid character marker
Solution: Use correct variable

CMake static library output does not match ZeroMQ Config.

Configuration used in ZeroMQConfig.cmake.in does not match to
explicic "libzmq" output of static build.

Problem: cmake artefacts different from make generated artefacts

Problem: typo in the zmq_has doc

Solution: fix it

add test and documentation for "draft" capability

Problem: cannot check if libzmq was build with draft api

As discussed in #2307

cmake: Set output name to libzmq for the libzmq-static target

Solution: Change the target output name from libzmq-static to libzmq.

Updated buildbase and buildall to work with visual studio 2017

cmake install on linux fixed

Problem: Thread-safe solution for modify hwm of pipe

Solution: where change pipe hwm, send a command (new type pipe_hwm) to peer, so peer pipe can modify hwm thread-safely

Problems: modifying pipe from different thread is not safe and HWM always boosted by 1

Solution: initialise *hwmboost to -1 instead of 1, and use it only if
it's >= 0. The socket option code checks anyway that the
user-provided value is >= 0 so there is no risk of clashing. The
documentation also specifies that it has to be >= 0.

Solution: revert change from #2299 to avoid bugs while we look for an
alternative and thread-safe solution

Problem: set hwm after connect lead to infinite hwm

Problem: spec file still depends on libuuid

Solution: remove the dependency as it's not been needed for a while

Problem: debian packages do not build manpages

Solution: build-depend on asciidoc and xmlto

Cmake win install

Windows cmake build fixed

Problem: peer can close connection before SO_NOSIGPIPE is set