Cache for the Inter-procedural Monotone Framework

[pdschubert]

To boost efficiency of the inter-procedural monotone framework a parameterizable cache should be integrated. Generating general summaries for non-distributive data-flow problems is usually undecidable, but at least one could cache a function's summaries for the last 10.000 contexts, for instance.

It probably makes sense to model the cache as a class similar to the FlowEdgeFunctionCache of the IFDS/IDE solver implementation.