Add support for road stop animation, availability callback

Add animation, callback mask, general flags properties
Add animation frame variables

src/newgrf_extension.h

@@ -45,6 +45,11 @@ enum Action0RemapPropertyIds {
 	A0RPI_ROADSTOP_CLASS_NAME,
 	A0RPI_ROADSTOP_DRAW_MODE,
 	A0RPI_ROADSTOP_TRIGGER_CARGOES,
+	A0RPI_ROADSTOP_ANIMATION_INFO,
+	A0RPI_ROADSTOP_ANIMATION_SPEED,
+	A0RPI_ROADSTOP_ANIMATION_TRIGGERS,
+	A0RPI_ROADSTOP_CALLBACK_MASK,
+	A0RPI_ROADSTOP_GENERAL_FLAGS,
 };