Adds a verb for rideable mobs to toggle rider control without a riding crop.

-Mountable mobs/borgs/taurs can now let the rider in control without requiring a riding crop.
-And yes, riding crop has always been "the key" for rider control for these mechanics.
-Also tweaks the AO a little bit more because ouch my ocd.

code/modules/vore/appearance/update_icons_vr.dm

@@ -44,6 +44,7 @@ var/global/list/wing_icon_cache = list()
 			if(taurtype.can_ride && !riding_datum)
 				riding_datum = new /datum/riding/taur(src)
 				verbs |= /mob/living/carbon/human/proc/taur_mount
+				verbs |= /mob/living/proc/toggle_rider_reins
 			return image(tail_s, "pixel_x" = -16)
 		else
 			return image(tail_s)