Add unit tests skeleton. Create MVC packages.

Add unit tests files in tests package, main file and file for core
classes. Create packages from MVC pattern, model, view, controller.
Tournaments module move to model package.
Add test_competitor method. Add function skeleton for other tests.
Add Score class tests. Fix Error classes for bad parameters (ValueError)
Add MatchInfo unit test.
Add test of Match class.

All core class tests is finished. Last test will be
SingleEliminationTournament class unit test.
Add unit test of SingleEliminationTournament class.

Close #2.