EMI: Chore fading fixes.

Fading out chores remain in playing state until they have completely faded out. Also using StopChore on a fading out chore will actually stop the chore, unlike in Grim where the chore will keep fading out.
EMI: Do not animate bones if weight is not >0.
EMI: Never fade rest chores.
Fixed implementation of AdvanceChore.
EMI: Fading tweaks.
EMI: Only update playing chores.
EMI: Animation code cleanup.