Wait for TexturePreloader before displaying board

[azeier]

This displays Waiting for assets... and Waiting for textures... before the game starts.

The reason behind heroPowerCount: If the assets load faster than the replay file (usually the case), working will be 0 between assets and textures being loaded.

TODO:

• Delay playing the replay until textures and assets are loaded.
• Add a better loading screen :).