Added `Game.hpp` header. With lines, quiet.
Added `Game` class
Added `start` method to `Game`
Added pure virtual `onInitialize` method to `Game`;
Added pure virtual `onFinalize` method to `Game`;
Added pure virtual `onDraw` method to `Game`;
Added `initialize` method to `Game`;
Added `finalize` method to `Game;
Added `quit` field to `Game`
Added some `TODO`'s