Add reserve through action to trace restrict programs.

This only changes the behaviour of PBS reservations which
would otherwise terminate at a PBS signal.
If the signal restriction sets the reserve through state,
the reservation continues through the signal, and the signal
is set to green.

src/pathfinder/yapf/yapf_rail.cpp

@@ -97,7 +97,7 @@ private:
 				m_res_fail_td = td;
 			}
 		} else {
-			if (!TryReserveRailTrack(tile, TrackdirToTrack(td))) {
+			if (!TryReserveRailTrackdir(tile, td)) {
 				/* Tile couldn't be reserved, undo. */
 				m_res_fail_tile = tile;
 				m_res_fail_td = td;