* python/dbus.py: Add the actual message when calling the reciever
of a signal such that parameters can be inspected. Add the method
remove_signal_receiver
* python/dbus_bindings.pyx.in (MessageIter.get): fixed typo in
argtype to arg_type when raising unknown arg type exception.
Changed type list to reflect the changes in dbus-protocol.h so
the bindings actually work.