Fix augm. dot metrics in mscore font

In the mscore font, the augmentation dot had an extra right side bearing, which resulted in extra space when used as dot for repeat bar lines and is presumably useless when used as an augmentation dot.

The right side bearing has been reset to 0.
Merge pull request #571 from mgavioli/Fix_mscore_font_augm_dot_metrics

Fix augm. dot metrics in mscore font