Added response to 'All Notes Off' MIDI message - Resolves #11

[autumnull]

Added a ctlin 123 object to the Linux plugin and the standalone, that triggers the stop button. I have not recompiled the files, nor made the same change to the other distributions for the plugin.

Side note: Camomile no longer supports VST2, so maybe switching to VST3 will be a good idea. I've found that the VST2 versions crash when opened alongside VST3 plugins in a plugin host, but the same issue does not happen when you compile for VST3 instead.