Brown Paper Bag - you can't just add pthreads, as GTK+ isn't exactly
thread safe by itself, you need to use gthreads, so do that.

Signed-off-by: Robin Getz <Robin.Getz@analog.com>
Merge branch 'master' into multi_plot_osc

Conflicts:
	osc.c
	osc.h
	plugins/fmcomms1.c
Fix major bug that was causing the application to crash.
Add the missing buffer_full variable.