fixes ofDrawBitmapStringHighlight issues

fixes an issue wherein the background rectangle would not be drawn at the correct position.

Note that the programmableGL renderer is more faithful in drawing the bitmap String since it uses the new internal ofMatrixStack to calculate the on-screen positions.

Closes issue #2212

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
removes unused matrix

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
Merge pull request #2215 from tgfrerer/fix-drawbitmapstring-highlight

fixes ofDrawBitmapStringHighlight issues