Add support for rendering key signatures in all clefs
Add support for rendering key signatures in all clefs

Silverwolf90/vexflow,aaronmars/vexflow,jmahmud/vexflow,spencerhitch/vexflow_extended,Silverwolf90/vexflow,Silverwolf90/vexflow,Huji/vexflow,Tails/vexflow,Tails/vexflow,Huji/vexflow,spencerhitch/vexflow_extended,aaronmars/vexflow,aaronmars/vexflow,Huji/vexflow,jmahmud/vexflow,spencerhitch/vexflow_extended,jmahmud/vexflow,Tails/vexflow