- removed all remaining native parts of APlayerPawn.

Unlike the other classes, the places where variables from this class were accessed were quite scattered so there isn't much scriptified code. Instead, most of these places are now using the script variable access methods.
This was the last remaining subclass of AActor, meaning that class Actor can now be opened for user-side extensions.

src/dobject.cpp

@@ -503,7 +503,7 @@ void DObject::StaticPointerSubstitution (AActor *old, AActor *notOld)
 	{
 		if (playeringame[i])
 		{
-			APlayerPawn *replacement = static_cast<APlayerPawn *>(notOld);
+			AActor *replacement = notOld;
 			auto &p = players[i];
 			
 			if (p.mo == old)					p.mo = replacement, changed++;