fix: Lua: Runtime error from mod 'animalia' attempt to call global 'cos'/'sin'/'vec_center' (a nil value)

api/behaviors.lua

@@ -9,6 +9,9 @@ local random = math.random
 local ceil = math.ceil
 local floor = math.floor
 local rad = math.rad
+local cos = math.cos
+local sin = math.sin
+local vec_center = creatura.vec_center
 
 local function average(t)
 	local sum = 0
@@ -1620,4 +1623,4 @@ creatura.register_utility("animalia:mount", function(self, player)
 		end
 	end
 	self:set_utility(func)
-end)
+end)