Builtin: Add vector.floor helper function

builtin/common/vector.lua

@@ -31,6 +31,14 @@ function vector.normalize(v)
 	end
 end
 
+function vector.floor(v)
+	return {
+		x = math.floor(v.x),
+		y = math.floor(v.y),
+		z = math.floor(v.z)
+	}
+end
+
 function vector.round(v)
 	return {
 		x = math.floor(v.x + 0.5),
@@ -130,4 +138,3 @@ function vector.divide(a, b)
 			z = a.z / b}
 	end
 end
-