Brateval formatter should be configurable

[aalbahem]

Brateval has many components such as output formatter, however, it does not provide an easy to override the default. If someone wants to change the report, they can not. They have to change and compile the code. This issue is to refactor the output formatter so it can uses the right formatter at run time.

I am going to add more later.

[aalbahem]

See #2