Excluded the main AssistantPerformer Form

The C# version of the assistant performer is no
longer supported. However, code in the
Moritz.Performer project/namespace is used to
play sounds in palettes. This is currently not
working, and is being debugged.
Reprogrammed MoritzForm1 so that it can no
longer open an AssistantPerformer Form.
The AssistantPerformer Form is no longer being
programmed, but it is still being tracked by Git
(for archive purposes).
Midi AudioControlButtons working in palettes.

The buttons now work without having to rely on
any old Assistant Performer code.
(They work entirely inside the MidiChord class.)
TODO: remove any unused objects from the
Moritz.Midi project.