Moved CompositeRenderer to the correct package.
Javadoc fixes.
Added a test case.
Added test cases for isFullLine.
Added a test case for GameLoop.
Added null checks.
Added a constructor to allow passing in a custom tetromino generator.
Simpler constructor for CompositeRenderer.
Renamed class.
Added a test case for TinustrisEngine.
Improved Javadoc.
Added a test case.
Formatting.