FMCOMMS1: Add support for DAC buffer.
ALL: Fix waveforms path.

Conflicts:

	config.h
fmcomms1.glade: Add back some elements that glade deleted without my consent.
FMCOMMS1: You can't use gdk_threads_enter/gdk_threads_leave in a
          call back, or things hang when trying to get the lock.

Signed-off-by: Robin Getz <robin.getz@analog.com>
THREADING: Fix issue with sometimes crashing, when stopping/starting when a plugin was asking for the data.