python: Integrate into the build system.
* configure.ac: Make Python bindings configurable, add new Makefile. * lang/python/Makefile.am: New file. * lang/python/setup.py: Integrate into the build system. * m4/ax_pkg_swig.m4: New file from the autoconf archive. * m4/m4_ax_swig_python.m4: Likewise.
- Signed-off-by: Justus Winter <justus@gnupg.org>