Grease spell lingering effects, stirges not attacking, sneak attack issues

[ALFAIthildur]

1. Grease spell effect lingers on party members long after duration should have expired after combat ends - longstanding issue that was supposedly removed a couple patches back but it seems it's still there.
2. stirges do not attack - at the start of an encounter with them the combat music starts and the party goes into combat animation, but actual combat does not start as the stirges do not attack during the opening round. The only way to get them to attack is by manually starting combat and attacking one of them; if it survives then it attacks during it's turn (but the other stirges may not-once the attacked stirge is slain combat ends and the rest remain neutral apparently).
3. low level party rogues are able to sneak attack enemies (ambush assassin, Ranos Davil) that should not be sneak attackable due to having much higher rogue lvls and uncanny dodge

[dolio]

For 3, I'm pretty sure improved uncanny dodge is fine. The problem is that various things that enable sneak attack don't check for normal uncanny dodge. So for instance, if you're flatfooted, your sneak attack status is just set to 1. It only looks at uncanny dodge for the AC check (even though that's technically what determines whether you can be sneak attacked). I think invisibility/blindness probably work the same way.

I also noticed there's some other fishiness w/r/t rogue features. So I might do a pass that fixes up the above and the other stuff.