* Fix ChangedValueChecker to use search instead of type hierarchy

- fix for #1317
- fix ChangedValueChecker.findFunctionDefinition() method so that
  instead of creating a type hierarchy for the project, first check
  if the declaration of the method is in a class with source in
  which case find the definition and if the declaration is in an
  interface, use SearchEngine to find implementers of the interface
  and process all finds for a class with source