Added comments
Added === and !== in addition to == and !=
Added firstOrNullIsInstance and firstIsInstance methods
Changed way to pass statementFilter from ElementResolver into ExpressionTypingServices
Partial body resolve: found group of cases incorrectly handled by the current implementation
Added a test
Partial body resolve filter: changed algorithm so that all statements to resolve are found when constructing it
Partial body resolve filter: more correct lambda resolve for return
Partial body resolve tests: more informative test output
Minor
Partial body resolve: rewritten algorithm of filter building to ensure correct resolve of smart cast points (+ prepared to support more strict mode for resolve only)