PRINCE: Revert incorrect const'ness at printAt()
CGE2: Fix bug #6733.

The problem was that the engine used the SFX volume for later parts of speeches longer than one sound file.
PRINCE: Attempt to fix compilation on AmigaOS
PRINCE: Reduce the scope of several variables in Hero
PRINCE: Reduce the scope of several variables in PrinceEngine
PRINCE: Reduce the scope of several variables in GraphicsMan
PRINCE: rename a couple of variables named "rand"
MADS: Fix loading correct backgrounds during animations