Add Three Voice Per Stave With Rest Repositioing

formatter.js :: Correct spelling error in comment.

modifiercontext.js :: Rewrite formatNotes to support three voices per
stave and automatic rest positioning to avoid collisions

note.js :: Correct doubling of note widths

stavenote.js :: Calculate rest bounding boxes. fix ledger lines for
rests above/below the stave, and new functions for setting stem lengths
and manually displacing notes.

tables.js :: Add glyph parameters for rest bounding box.

vex.js :: Correct spelling error in comment

flow.html :: add tests for three voices per stave formatting

threevoice_tests.js :: New tests for three voices per stave.
Remove spurious comment.
Ignore barlines and other non-tickables for rest alignment.
Correct y position for 'inline' articulations
get real width & height for ctx.clear method
Colors and glow for individual keys in stave notes.
- implement custom padding
- added tests for padding
- implemented 128th note/rest
- added 128th note/rest glyphs to Vex.Flow.Font
- added tests for 128th note/rest support
Fixes issue drawing a stavenote with two consecutive notes on the same line. Sometimes the second note is masked by the first and not visible (i.e. displaced) as expected.
Merge branch 'upstream-colors' of github.com:bpartridge/vexflow
add strokestyle to keystyle options
set key styles on modifers too
Merge pull request #122 from arthurian/master

Correct displacement of stavenote keys on same line.
Merge pull request #121 from Nairam/feature/128th_note_support

128th note support
Merge pull request #120 from Nairam/feature/customPadding

Custom Padding for correct alignment of time signatures in multi-instrument setting.
Merge pull request #101 from rsml/dev/rsml/articulations

Correct y position for 'inline' articulations.
Merge pull request #109 from mchen745/master

Get real width and height for ctx.clear method.
Added inheritance helper to vex.js. Made Accidental use new
inheritance pattern.