Fix stave getNoteStartX and getNoteEndX
Fix stave getNoteStartX and getNoteEndX

getNoteStartX: modifiers.length > 2 does not match the existence of other left clef, key signature or time signature. change to use glyphs
getNoteEndX: it should consider the case of end barline REPEAT_END, use same gap value(20) which is for REPEAT_BEGIN

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