readQuarterNotes: Identify quarter notes on a staff and name them

This code uses template matching to find quarter notes on a staff
and locate the center of their positions.  It also identifies staff
lines to find note names.  Currently only works for a single line.
Also might not work for other images than the ones currently included,
need to automate choosing parameters for template matching
Merge branch 'master' of https://github.com/sarahwalters/piano-poe