Make setup.py work with Windows: - introduce check_executable_unix and...

Make setup.py work with Windows: - introduce check_executable_unix and check_executable_windows and use them appropriately - use subprocess.check_call instead of os.system to catch make compilation errors - force makefile to use the pyuic detected in the check_executable (needed to have PYUIC=pyuic4.bat work correctly) - do not compile qvideoboob on Windows because it requires phonon