Refactor: split up feature model anomaly solver into different anomaly types

[schweikart]

the only real overhead of this approach is the additional meta solver, which is valid and perhaps even desired.

We might even be able to get rid of that. We could implement an abstract SingletonProblemSolver extends ProblemSolver implements MetaSolver that implements the MetaSolver methods automatically. This could be used for problems with only a single solver.

[Elscrux]

We might even be able to get rid of that. We could implement an abstract SingletonProblemSolver extends ProblemSolver implements MetaSolver that implements the MetaSolver methods automatically. This could be used for problems with only a single solver.

I'd rather keep it as it is, as a SingletonProblemSolver kind of goes against the point of a MetaSolver which should handle multiple solvers. We might not want to create another solver for something like a dead features anomaly in feature models, but at least we support it.

[schweikart]

I've fixed toolbox-web to use this new route scheme in https://github.com/ProvideQ/toolbox-web/pull/25

[schweikart]

I've finally gotten to revising this PR now :sweat_smile:

If this works for you now, please merge this PR into refactor/controllers first so the tests over there pass as well. Then we can merge #39 as well :)