Update Bach BWV-988 var16

\time 4/4->2/2
bar5: treble clef, ornament prallprall->prallmordent
bar15: add turn
bar18: add turn (Javier Ruiz-Alma: no turn in Gesellschaft, but noted on Nuremberg)
bar48: incorrect b in treble clef, should be octave lower in the bass
bar9:  bass clef, first 2 beats split beam
bar32: treble clef, lower voice, last "g"->"gis"
bar32: treble clef upper voice first "d"->"e"
(Steve Shorter)
Update to v2.16.1
Rest, slur, tie alignments
bar 6: bass 1st "c" add prallmordent
bar 7: treble 1st beat add arpeggio
last bar: add termination
(Javier Ruiz-Alma)
close #65