US: As a user I should be able to generate a game

Modified Settings.py to include MODERATE and HARD game levels
Modified __eq__ to include the case where comparison is made with an object that is not instance of Level class
Modified SodukuBoard to include the character '.'
Added game_generator and solver_algorithm to Game class. Setters were also added
Added unit test for Recursive class. Coverage is now 100%
Implemented Generator class
Implemented GameGeneratorCommand class

Reviewer: Ines Baina

Signed-off-by: xaindeneb <xaindeneb@gmail.com>
Merge pull request #8 from pysudoku/creategame

US: As a user I should be able to generate a game