simple stupid scope
-------------------

Demonstrate the short-comings of LV2 thread synchronization and LV2Atoms for
visualization UIs.

LV2Atom messages are written into a ringbuffer in the LVhost in the DSP-thread.
This ringbuffer is sent to the UI in another thread (jalv and ardour use a
g_timeout() usually at 40ms ~ 25fps), and finally things are painted in the
X11/gtk-main thread.
