Adding Py3k support.
 * Modified 'setup.py' to automatically execute 2to3.
 * Modified 'setup.py' to install Py3k compatible dependencies.
 * Moved 'bin' dir into module to include it into automatic 2to3 conversion.
 * Modified 'media_dir_walker' to use Py3k's 'os.walk' instead of 'os.path.walk', if required.