Add USE_ALLOC_MONITOR and USE_LATENCY_MONITOR as options

This allows to build multiple versions of library from single source
without modifying source each time.

E.g:

    mkdir build_lat_mon
    cd build_lat_mon
    cmake .. -DUSE_LATENCY_MONITOR=ON

You can also see all the options from menu:

    ccmake ..

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Paul Colomiets added to the AUTHORS file

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Merge branch 'master' of github.com:250bpm/nanomsg