Adding clearStates() method into IGameStateManager and inheritors.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
IRoot and inheritors are basicaly implemented.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
Minor: TODO in IGameState.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
IGfxManager and inheritors are partially implemented.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
IntroState finished.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
MainMenuState is finished.

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>
Game without input.
Kruzhochek class ia dded; KruzhochkiState is implemented - scene is OK, but no input;

Signed-off-by: Stanislav Demyanovich <stan@angrybubo.com>