GRIM: Fix ActorToClean behaviour. Bump save version to 22.4.  Fix #701.

The clean buffer code needs two layers. Every actor needs its buffer,
but we also need a global one. The actors' buffers blit to the global buffer
which then gets blitted to screen.

(cherry picked from commit 80109ca3fe4fe540dc650f89b29b81dd2e157a37)
GRIM/iMuse: If we're starting a sound which is fading out bring it back. Fix #246
(cherry picked from commit b385867f6d3b17369334fae5988683f77f6d56a8)
GRIM: Don't push a costume if the actor has it already in the stack. Fix #483
(cherry picked from commit 3dc7fc4e942ed80d9163f7f6680aba3e7aaf51cf)