Stream type to support collision_box, collision_mask

[Earendel]

Please allows the stream type prototypes to support collision_box and collision_mask properties so that they can be blocked by things like walls.

[Rseding91]

But the stream goes over the walls? Also the fluid stream was specifically coded to not do any collision checks while moving so it doesn't waste performance. Just like robots - they never check collision - they simply move when told they need to move.

So, this is not likely to happen.