Right now this has a re-work that gets rid of the split between HitBox and RotatableHitBox. Originally this split was decided on because hitboxes are expensive to rotate, but in practice we've not really realized any gains from this, and everything is nearly universally always using RotatableHitBox anyways, so I think this split is not worth the headaches it has caused.

In addition to removing that split, it supports multiple polygons per hitbox, and they can be named. Yet to be done is to allow the collision detects to report what regions were collided, so you could do things like check if a head region or an arm region were hit. Obviously using multiple regions will incur a greater performance hit, as the check is a similar cost per region, but this can potentially save users from needing to manage things by composing a character or something out of multiple sprites.

The new hitboxes also support being loaded from JSON, I have plans to build an editor for creating these points, but that is not done yet.

Another thing yet to be done, is to update the Tilemap loading to support loading multiple regions from Tiled objects, this is something Tiled supports but Arcade has historically ignored. I will have to investigate how the region naming should work for loading these, but I believe the objects in Tiled can be given names, so that will probably be the way to go.

I removed a commit for experimenting with a channel/mask based collision system similar to Godot's, I still think it's an interesting idea but I think it only makes sense if we completely revisit physics/collision control in Arcade. It's still largely up to the user when to actually perform collision checks and what things they perform them against, and the channel/mask system only feels like it really makes sense if Arcade were just constantly running a physics/collision system that users could hook into.