dbus-python 0.80rc1 release candidate

[Simon McVittie]

Oh, another issue I want to fix before 0.80: introspect data is parsed
with libxml2. This seems a bad move, since Python is usually (always?)
linked with expat, which is a perfectly good XML parser and also rather
small, and the D-Bus daemon is generally (always?) also linked with expat
rather than libxml2.

I've also been getting occasional segfaults during exit which appear to be
caused by a bad xmlBufferFree() in the libxml2 bindings. I'm not quite sure
what's happening there, it used to work...

	Simon