* bus/test-main.c, dbus/dbus-test.c (main): check memleaks
after every test so it's quick and easy to see which leaked, and
so we test multiple dbus_shutdown() calls
* configure.in: change configure.in XML stuff to also support
expat
* config-loader-libxml.c: some hacking
* config-loader-expat.c: some hacking
* config-parser.c: some hacking, plus tests
* throughout - add more _DBUS_ASSERT_ERROR_IS_CLEAR
* configure.in: add --with-xml option to specify XML library,
right now only libxml is supported.
* bus/config-loader-libxml.c, config-parser.c: sync some minor
nonworking code between home and work, still just stubs