Lock-step Solving and Timeout for IDE Solver

[fabianbs96]

Currently the solve() method on the IDESolver cannot be interrupted once started. This is not problem for analyzing small target programs, but is unacceptable for larger analyses that may run for days.

This PR adds fine-grained control over the solving process while still abstracting the solver internals.

The abstraction consists of three basic functions: initialize, next and finalize.
They are being called according to the below flow-chart:

flowchart LR
  initialize-->|true| next
  initialize-->|false| finalize
  next-->|true| next
  next -->|false|finalize

Loading

In addition to these basic APIs there are convenience functions like solveUntil, solveWithTimeout, etc. that build upon this model.
The original solve method has been rewritten and makes use of this model as well while keeping its original semantics.

Further, the solving methods (including finalize) now return a view into the solver results (or owning solver-results when called with an rvalue-reference) for allowing to be used in a more fluent way.

[MMory]

lgtm, it is good to have this, thank you!