- more cleanup on portal implementation:

- store portal data in a separate structure.
- store portal data in savegames because some of this will be changeable later.
- run a cleanup pass after all portals have been created to weed out broken ones.
- add a definition type that's compatible with Eternity Engine's line portal types.
- swapped arg[2] and arg[3] of Line_SetPortal, because the type is more significant than the alignment.

src/p_spec.cpp

@@ -1504,6 +1504,7 @@ void P_SpawnSpecials (void)
 	}
 	// [RH] Start running any open scripts on this map
 	FBehavior::StaticStartTypedScripts (SCRIPT_Open, NULL, false);
+	P_FinalizePortals();
 }
 
 // killough 2/28/98: