0.7 requires dbus 1.1 or greater (for system bus activation), so make that
explicit, and remove compat code for D-Bus 0.6 and earlier. Consolidate
the various glib pkgconfig checks into one, since most anything will require
gthread, glib, and gobject anyway. Fixup the docs makefile to be more
automake-compatible and let 'make clean' actually work correctly when
docs are built.
Clean up handling of "special" keys in keyfiles, ie ones that
need more processing than the basic GKeyFile API supports. Add
MAC address reading (writing support to come).
Additionally, add some test bits for the keyfile plugin that get
run on 'make check'.
