Application graph added. Reachability-related methods not implemented…

Application graph refaqctoring.

ApplicationGraph is a collection of CFGs with asynchronious communication interface.
CFG constructing refactored. Exceptions do not supported yet.
cilState is IGraphTrackableState to allows graph query engine to map information to state directly.
API is exactly the same as used for CFPQ. So, it should be easier to merge CFPQ in the future.
API calls added to interpreter, so some not implemented method do not throw exceptions to prevent tests failing.
Distance-related functions in searchers a stubbed for now.

VSharp-team / VSharp