- Fixed: PIT_FindFloorCeiling required tmx and tmy to be set but

P_FindFloorCeiling never did that.
- Merged Check_Sides and PIT_CrossLine into A_PainShootSkull.
- Replaced P_BlockLinesIterator with FBlockLinesIterator in all places it was
  used. This also allowed to remove all the global variable saving in
  P_CreateSecNodeList.
- Added a new FBlockLinesIterator class that doesn't need a callback
  function because debugging the previous bug proved to be a bit annoying
  because it involved a P_BlockLinesIterator loop.
- Fixed: The MBF code to move monsters away from dropoffs did not work as 
  intended due to some random decisions in P_DoNewChaseDir. When in the
  avoiding dropoff mode these are ignored now. This should cure the problem
  that monsters hanging over a dropoff tended to drop down. 

SVN r887 (trunk)

src/p_mobj.cpp

@@ -3642,6 +3642,7 @@ APlayerPawn *P_SpawnPlayer (mapthing2_t *mthing, bool tempplayer)
 	p->damagecount = 0;
 	p->bonuscount = 0;
 	p->morphTics = 0;
+	p->MorphedPlayerClass = 0;
 	p->extralight = 0;
 	p->fixedcolormap = 0;
 	p->viewheight = mobj->ViewHeight;