Remove Sound/Ui/Status objects from game
Game: store Video and Image as references

Don't store the Video and Images objects within class Game.  Instantiate
them outside.

They're stored inside class as references rather than pointers to avoid
having to change the code to use pointers.
game: Put game data arrays into struct

This allows the data size to be determined by calling sizeof() on the
struct.

Also dump the memory required for one GameEntity.

Current stats on AVR:
Game data size: 3257 bytes
Game entity size: 17 bytes
game_entity: Use auto bit fields for flag variables

No need to manually check/set the bits.
game: publish game entity type property data size

Currently 396 bytes.