Song Time Signatures

[swesterfeld]

Anklang currently has a way to specify that you want to use something other than 4/4 as time signature for your song. However, doing so doesn't have any visible effect. So the piano roll widget still displays everything in 4/4, both in the timeline and in the grid inside the piano roll.

We should also have a way to change the time signature within a song. This is not so common, but does happen.