The merge-rests-engraver keeps double dots. #123
Description
When using dotted rests, the merge-rests-engraver will just merge actual rest symbol, not the dots. I have prepared a little lilybin file to show what I mean: http://lilybin.com/r1jcpm/3
I'd like the first (merged) rest to appear just as the second one. The third and fourth example show that with different dottings they are merged even though they represent different durations.
I played a bit around with the Scheme code but didn't come very far, as apparently the dots belonging to the rest are not connected at this level. I'll gladly work on a PR for this myself if someone can give me some pointers.