Custom setup.py libhadoofus clib building

Integrates a new build_clib command which supports additional arguments
in the setup(libraries=[...]) in order to compile on gcc. The Makefile
is used to pull in some of the compiler arguments using
distutils.sysconfig.parse_makefile which *cannot* read CFLAGS, LDFLAGS,
or CPPFLAGS by design, thus we declare PY_{C,LD,CPP}FLAGS.
setup.py structure, import of DistutilsSetupError