Generalize the scopes to make them more consistent

[smeyer198]

With the addition of the Opal scope, we had to refactor some parts in the scope structure because it was optimized for Soot. This PR contains some more internal refactoring to make the scopes more consistent:

• All scopes follow now the same structure; changing a part in one scope is applicable to the other scopes, too
• Refactor specific resolution parts that forces us to include classes that may not be required for the analysis
• Fix check handling of "PhantomFields" in BoomerangScope-SootUp #130 and Phantom Field Resolution Requires Full Library Inclusion While Seed Generation Ignores It #134 by using inly the field signatures as they provide all information needed for Boomerang

Close #130
Close #134

[swissiety]

great work - I guess I would not have passed around the scene singleton for Soot as this will most likely never be anything else than a global singleton.

[smeyer198]

@swissiety I added the suggested changes. I added the Scene object just to be consistent. It is also easier to document the scopes, e.g. "Each scope has a "master" object (Scene, View, Project) that is passed between the scope objects"