fixed dotshift for lines < 0
Fixed Staveline with Raphael
Made renderer methods consistent.
Added setLineDash to CanvasContext.
Merge pull request #205 from aerhard/master

fixed dotshift for lines < 0
Added draw_stem_through_stave render option for TabNote stems
- Refactored TabNote.draw() by extracting multiple methods
Add comments to TabNote
Fixed lint errors in TabNote.
Add duration based Crescendo class
Fixed lint errors.
Fixed textnote test.