- Current issues to fix in Rev Etude midi generation:

• Ignore stem above first line in tempo indicator, (done)
  
• Bar crossing two lines, (done)
• Key signature detection not picking up all elements. Found that some glyph runs are duplicated which could be related. Duplicated shouldn't be too hard to fix (tomorrow).
  
• Tied notes (including ties across lines :/ ),
• Stems in chords which don't overlap on X axis are interpreted as in separate chords

- Stems in chords will not overlap on X only if they overlap on Y.
- Stems may not have the same note value.
- Should check X position of stem before appending to voice. Position can't be absolute in bar but can be relative to previous stems and voice lengths.
- Can use chained stems in other voices as guide for where voices are up to in bar.
- Stems can't be new voice starting off beat.