Moved threshold to trigger object.

Also commented out debug message when checking if a signal group was playing a tone already.
Merge branch 'buttons' of https://github.com/mptouzel/MIDIDance into buttons
Consolidated gitignore file.
Minor cleanup.
Added simulated button presses.

This assumes that the button signal only changes instantaneously and is not changed for a period of time (which is possibly not accurate).
Correcting gitignore file