Flying mobs now clip past non flying mobs, various flightsuit/iontrail/movement tweaks/code improvements/bugfixes

code/game/area/areas.dm

@@ -460,14 +460,14 @@ GLOBAL_LIST_EMPTY(teleportlocs)
 		T = get_turf(src)
 	var/area/A = get_area(T)
 	if(isspaceturf(T)) // Turf never has gravity
-		return 0
+		return FALSE
 	else if(A && A.has_gravity) // Areas which always has gravity
-		return 1
+		return TRUE
 	else
 		// There's a gravity generator on our z level
 		if(T && GLOB.gravity_generators["[T.z]"] && length(GLOB.gravity_generators["[T.z]"]))
-			return 1
-	return 0
+			return TRUE
+	return FALSE
 
 /area/proc/setup(a_name)
 	name = a_name