CGE2: Refactor Hero::expand() and Sprite::expand().
CGE2: Fix saving of moving heroes.
CGE2: Fix initialization of volume switches.
CGE2: Prevent the engine from entering an endless loop when loading.

Also remove CommandHandler::reset(), since it's not useful anymore.
CGE2: Repair computation of save checksum.
CGE2: Fix loading during gameplay.
CGE2: Fixes for the FXP class
CGE2: Disable checking the sound options while the intro animation is running.

Since there are no toolbar during the intro, checking it's buttons would cause a crash.
CGE2: Remove dummies from save header and change save checksum.

The old saves are broken by our new FXP implementation anyway.
CGE2: Fix sunset() and sunrise().

Now they really do the fade-in/fade-out effect.
CGE2: Rearrange showTitle() and add some delay to the display.

Now the splash screen doesn't vanish almost immediately right after it's drawn.
CGE2: Comment out delay in the splash screen during testing.