(small comment update)

Also, I just tested the scan rate without debounce (lol, should have
thought of that before) and it's about 471Hz.  This is much faster than
the 200Hz (every 5ms) that we need to limit ourselves to due to the
switches needing a 5ms debounce time.  It should be trivial to tune the
scan rate to closer to 200Hz once I get lib/timer implemented.
(misc changes; additions for planning)