#268 introduction of qualifier

The solution is more-or less ready.

I need to add some additional tests to cover different kind of qualifying situations such as:
1. class
2. #method

Also I need to add test cases for the `@MapMapping` and `@IterableMapping`.
Yup.. I'll remove.. I adapted the example in general to be a bit more straightforward. Perhaps we should have a repository of good examples that we can use to model our test cases on :smile: