Switch to autotools and test with Python 2.5 as well as 2.4.

In the process:

HACKING.txt: update
include/dbus-python.h: add some typedefs to make it saner
bus.c, conn.c, conn-methods.c: further alter docstrings to keep epydoc happy
exceptions.c: create exceptions in a more longwinded way for Python 2.5 compatibility
message-get-args.c, bus/__init__.py: tweak docstrings
dbus/introspect_parser.py: make docstring valid reStructuredText
run-test.sh: simplify, since configure now does some of the work
test/*.py: use paths from run-test.sh, cope with out-of-tree builds
test-standalone.py: carry out additional sanity checks