Gst::AudioClock: auto generate some audioclock methods

Those methods used to have object of GstClock type  as a
first argument, so had to be wrapped manually. It has been
fixed inGStreamer (https://bugzilla.gnome.org/show_bug.cgi?id=756628)
in version 1.12.0

https://bugzilla.gnome.org/show_bug.cgi?id=783628