add new animation type for MMST

Fixes animation erros and invisible mist when slaying vampires in BG2.
only reenable spawns when the party has moved away some

If the spawn point is just out of sight it often respawns immediately,
attacking the party that is moving away from it from behind.
don't mess with ItemInfoWindow if we go straight to ItemWindow

Fixes a Python error when opening a container.
be less strict when initiating dialog

Requiring line of sight can easily break some of the game scripts
when the party is positioned in a way that keeps some members
invisible. I've seen it break both BG1 and BG2 in places.

It also means that if "the party" sees someone you'd like to talk
to but the party leader himself doesn't, clicking on the target
won't initiate dialog.
don't auto-identify items when they are put in a bag
get rid of duplicated item creation code
try harder to find items to aggregate in shop listings

Many items that don't use charges (e.g. weapons or armour) come
with bogus charges, and if the shop fails to take that into account
there'll be mutiple listings of those items in the item list.
share item sanitation code between item loading and creation

Also use it for shops.
DragItem: don't care about BAM cycles for the dragged image

Fixes SCRL7E going invisible when dragging because the BAM doesn't
have any frames in cycle 0.
make MSVC happy
rewrite OpenStoreRentWindow so as not to require UpdateVarAssoc
clean up handling of bad/invalid item properties by forcing sensible defaults
don't leak the item info
improve error reporting when a bag is full
don't reactivate spawn points with living spawns in the area
don't place persistent actors again for already loaded areas

Fixes CheckForReplacementActor spawning multiple copies of replaced
actors on area transition. Also truly delete replaced actors, and
fix an off-by-one error in the replacement loop.
fix leak when buying items from a store
some general changes in preparation for IE_ANI_NINE_FRAMES update
allow multiple palettes for dragon animations
fix dragon attack animation