commit bd01a94e669e5f78dca45cb8bfc41d8e29cc2fe4
Author: Rinat Ibragimov <ibragimovrinat@mail.ru>
Date:   Sun Feb 14 19:22:51 2016 +0300

    make traceing level configurable
    
    -DWITH_TRACE=<trace-level>
    
    0: no tracing, only warnings and errors
    1: unimplemented functions
    2: all
