pyx source files are now used only when USE_CYTHON is set to 1 or the
C source files have not yet been pre-compiled.
Only efl.eo.c is checked for this so if you cancel an initial build make
sure to enable USE_CYTHON when re-starting the build.
The pyx sources will now be included in the source tarball.
* Fix clean_generated_files to also include utils
* change format() usage to simple str concat...just to hurt kuuko :)
* remove the usless check for __main__