Fix most lint errors in stavenote.js + minor refactorings.
Fix most lint errors in stavenote.js + minor refactorings.

aaronmars/vexflow,Huji/vexflow,Silverwolf90/vexflow,Tails/vexflow,Silverwolf90/vexflow,Tails/vexflow,Silverwolf90/vexflow,Huji/vexflow,Huji/vexflow,Tails/vexflow,aaronmars/vexflow,aaronmars/vexflow