[+] Test#4[closed] bug in invocation eater is resolved
     - methods in lambdas inside the Mock.Of<>(..) was interpreted as TargetCall (of course)
     - so the separated MoqStub eater's subsystem was added
     - also new subsystem in future will be able to collect moq options for metric
[+] some other refactorigs
      - common interface ICsharpNodeEater is introdused - it is layer supertype
      - some guard expressions are added