This is a new test facility for checking note on and note off behaviour. It is
disabled by default and enabled at compile time in ccmake as "ReportNotes".

When enabled it continually checks that all notes at their entry to Yoshimi are
passed on the the actual note on/off code and reports any differences to the reports
console or stdio (whichever is selected).

When working entirely within jack (including LV2) there should be no messages at
all, but if using ALSA for either MIDI or audio there will sometimes be a few
different depending on the complexity due to the buffering action.

At any time hitting the GUI stop button will report the totals. However, this report
is done *before* the stop cleanup so will show any notes that were still in the ring
buffer at the time stop was hit.

When you stop playing or a MIDI file has finished is the best time to check. You
will then see the totals and there should be none shown as different.

The master reset will zero all of these figures.

Yoshimi's virtual keyboard is not supported by this system and will actually produce
negative numbers!

Bear in mind you can have more note_ons than note-offs as two note_ons at the same
pitch and channel will both be cancelled by a single note_off. These will be
reported as 'hanging' notes.

This last point is no longer true. Note_on events are counted and will require the
same number of of note-off events. However, if you change the incoming channel
number while a note is playing *within Yoshimi* the incoming counts will be correct,
but there will be notes still sounding.