Fix arc rendering bug (make vertex attribs correct size)

shader/ellipse.frag

@@ -4,7 +4,6 @@ in vec4 gColorE;
 in vec2 gBoundingBox;
 
 out vec4 fColor;
-//out float gl_FragDepth;
 
 void main()
 {
@@ -12,4 +11,3 @@ void main()
   if ( d > 1) { discard; }
   fColor = mix (gColorE , gColorC, d);
 }
-//note it is the fragdepth that stops this from being square