add vtest for various recent mmrest fixes

This adds a vtest for the following mmrest fixes:

http://musescore.org/en/node/33381 - start repeat bad layout with mmrest
http://musescore.org/en/node/32826 - end repeat not shown at end of mmrest
http://musescore.org/en/node/31436 - repeat text not displayed in mmrest
http://musescore.org/en/node/14146 - text should be displayed over but not break mmrest http://musescore.org/en/node/31711 - same as above for chord symbols