* python/dbus_bindings.pyx

* python/dbus_bindings.pyx
(_pending_call_notification, cunregister_function_handler,
cmessage_function_handler): All callback functions have been rearranged
to workaround a bug in Pyrex when working with the GIL which is Python's
global lock when dealing with threads.  They have been split into
a wrapper function (which assumes the name of the old function) and
a _GIL_safe_<function name> function which contains the functionality
of the old function.  This ensures that Pyrex does not write code
the lock is released.