Maestro: Layer Editor visual enhancements

[jbirch]

• Currently, the layer editor uses fixed heights for its dialogs. This means that if you add more than three rules to a style, you can not see the lower ones.

• It is difficult to locate specific scale ranges, and I found the interface a bit non-intuitive. I clicked on "Add Scale Range" and apparently nothing happened (it had, but I couldn't see it because it was below the fold). I wonder if this would work better as a scale tree on the left and tabbed style definitions on the right?