Experimental Testbed Program For GUI/UX Stuff

Features To Explore
-------------------

- Midi Learning
- General OSC connectivity
- Undoing/Redo
- General Parameters Organization

How to Use
----------

Left click on schematic elements to reveal local controls

Within the control panels
~~~~~~~~~~~~~~~~~~~~~~~~~~

1) Left click   - normal
2) Middle click - midi edit window (we'll get to that later)
3) Right click  - quick learn

For MIDI learning, there is additionally an overlay to show the current status
of the system.
This can be toggled by clicking on MIDI in the upper right
(clicking undo does nothing).
Now when learning with the overlay on, one click will learn the coarse control
and another will record the fine.
Mapping many things at once is quite simple and encouraged (though the overlay
might start getting a bit weird if over 26 are ever pending at once).
These can be killed off in the midi edit window which you can get to via middle
click.
In this window the size of the scaling, the type of the scaling (this is
disabled for now) and the mappings can be edited.

On the right there is an undo stack currently capped to 20 events.
Clicking on any of those entries will revert the state to a prior point in time.
If a parameter is changed within 2 seconds of it's last change this is merged in
to a previous undo event (so wiggling groups of controls around does not
flood this window out).

Anything sent from the window results in some virtual midi events when
parameters are mapped, so moving mapped widgets or using undo should send out
the proper undo events.

Build deps:
- A recent version of rtosc [ https://github.com/fundamental/rtosc ]
- A recent version of ntk or fltk>=1.3.0