add --quality for controlling ffmpeg encoding quality
sanitiseLy(): handle various spaces gracefully
getFilteredIndices(): improve debug
improve debug
getFilteredIndices(): improve docstring
getFilteredIndices(): improve progress message
fix bug with tied chords in repeated music sections

Tokens in the source file can be linked multiple times from the PDF,
if they are contained by a

    myMusic = { ... }

declaration which is then invoked multiple times.

We make the first value in the tuple the coordinate of the left side
of the box, in order that the tuples notePositionsInPage will be
sorted primarily left to right in the order they appear in the PDF,
and secondarily by the order they appear in the source file.
remove blank line
ticksToSecs(): drop midiResolution parameter which is already in an instance variable
keep track of current tempo in VideoFrameWriter instance

When the while loop in measureTempoChanges() bails immediately,
the tempo is not set, therefore we need to store it in the instance
when reading the initial tempo.
xsc2beatmap: fix missing interpolation when last measure of a section has no beats
pip-requires.txt: explain why my fork of python-midi is required

https://github.com/vishnubob/python-midi/pull/6
Remove set-global-staff-size which used a dubious calculation