New Score suggestions for improvement

[philxan]

A couple of small usability suggestions to the "Additional score information" page of the New Score dialog.

1. In the Tempo box, add a "Swing" check box.
   Mostly this would default to off, but for some templates (e.g. Jazz Leadsheet) this could default to being checked. It saves time & effort in setting up a chart. Currently this needs to be added after the score is created.

2. Make the tempo editable even if its not shown on the score.
   Currently the only way to set a tempo for a score is to have MuseScore show it. It would be great to be able to set the temp, but not have it displayed. The current work around is to set the tempo, and then hide it.

3. Add a "System Breaks every n bars" option in the Measures box
   Again, the templates preview a particular format - for example the Jazz Leadsheet clearly shows a system break every 4 bars. Others typically show 6 bars per system. The expectation is that when you create a chart from that template, that is what you get. Adding an option like this would again help optimise the workflow of creating a new score.