Still not possible to add new ones or delete existing ones, though. And the UI
for this is not finished at all. Work in progress.

Also some refactoring. To increase readability, introduce typedefs in
ScCalcConfig. Not sure whether nested types inside the class is a good idea or
not.

Change-Id: I8e1695bb0594e2cd5f8b5ce0ece075842b77762a