Fix some issues with changing player viewheight at runtime

- Viewheight change was delayed: Viewheight must be copied to player
  structure as well as the PlayerPawn. Not sure if should actually use
  deltaviewheight to spread the change out over a few tics instead of
  being instant.
- Viewheight not preserved when travelling: player->viewheight must be
  restored from pawn->ViewHeight, because the temporary player set it back
  to the default viewheight.

src/fragglescript/t_cmd.cpp

@@ -169,6 +169,7 @@ void FS_EmulateCmd(char * string)
 			{
 				// No, this is not correct. But this is the way Legacy WADs expect it to be handled!
 				if (players[i].mo != NULL) players[i].mo->ViewHeight = playerviewheight;
+				players[i].viewheight = playerviewheight;
 				players[i].Uncrouch();
 			}
 			while (sc.GetString())

src/g_level.cpp

@@ -1229,6 +1229,7 @@ void G_FinishTravel ()
 			pawn->lastenemy = NULL;
 			pawn->player->mo = pawn;
 			pawn->player->camera = pawn;
+			pawn->player->viewheight = pawn->ViewHeight;
 			pawn->flags2 &= ~MF2_BLASTED;
 			DObject::StaticPointerSubstitution (oldpawn, pawn);
 			oldpawn->Destroy();

src/p_acs.cpp

@@ -3899,7 +3899,13 @@ void DLevelScript::DoSetActorProperty (AActor *actor, int property, int value)
 
 	case APROP_ViewHeight:
 		if (actor->IsKindOf (RUNTIME_CLASS (APlayerPawn)))
+		{
 			static_cast<APlayerPawn *>(actor)->ViewHeight = value;
+			if (actor->player != NULL)
+			{
+				actor->player->viewheight = value;
+			}
+		}
 		break;
 
 	case APROP_AttackZOffset: