Alternative recursive tuplet filtering algorithm
O(1) instead of O(log N) tuplet indexes exclusion
Small optimization in tuplet exclusion
Add save/restore functions for valid tuplets
O(log N) instead of O(N) first chord in range search
O(log N) instead of O(N) end chord in range search
Fix quantization of prev-tied tuplets
Leave only 23 tuplets with min error for further filtering
Merge pull request #823 from trig-ger/midi_fixes

MIDI import: further optimization and fixes