#26, #27 - Minor changes.
#27,#31 - Cleaned up the reset case, providing a better distribution of
intelligence and layering of control.  This version works fine in
Verifier with the watch GUI.  It also fixes the problem with the GPS
timeout events mentioned for the previous commit.
#27, #31 - Minor updates (mostly comments) to TrackLog.addTrackPoint().
#27, #31 - Removed the last two attributes from TrackLog, as they were
unnecessary, leaving the question of whether the class should be
deleted.  For now, it will remain.
#27, #31 - Minor change to depend not on a singleton instance of track
log, but on a singleton instance of workout session, navigating through
the session to find the associated track log.