support percent values to set the tempo
It would be a nice feature to allow the usage of a percent value for tempo, based on a "basic tempo".
Why: often scores use tempo advices like:
- a tempo
Actually the user needs to "know" the initial tempo and set something lower for the ritartando and again the initial tempo for "a tempo". But what happens, if the user decides to change the general tempo? He needs to update all places like above.
Ideal would be to have a sort basis that is the tempo used in the beginning of the score. Later a user can then set %-values instead of absolute ones to set the tempo based on this.