Implemented TabNote stems and Beams
- Adds a StemmableNote class which TabNote and StaveNote now derive from
- Renames 'noteGlyph' property to 'glyph' in TabNote (possible confusion between TabNote.glyph and TabNote.glyphs, the former is for storing duration glyph data and the the latter is for storing the fret position data)
- Extracted out a drawStem() method into StemmableNote
- Beam drawing now calls StemmableNote.drawStem() instead of its own stem drawing logic
Added TabNote stem extensions
Fixes TabNote beam slope bug
Set StemmableNote stem_direction on init
Minor Tweaks
- Add in duration aliases where applicable
- Slight refactor of TabNote.getStemY() for clarity
- Adds setmmablenote.js to Rakefile
Added dots for TabNote stems
Fix lint errors and add copyright message.
Add built version of vexflow to repo.
Merge pull request #149 from panarch/master

Added support for inserting clef on the middle & end of a Stave.