* dbus/Makefile.am: split lists of sources into stuff that goes in
	the library, util functions that go in the lib and are also used
	elsewhere, and util functions that are used in tests/daemon but
	don't go in the lib.

	* dbus/dbus-mainloop.h, dbus/dbus-mainloop.c: move bus/loop.[hc]
	here so it can be used in test binaries also