RFC: Remove collision types and traits

[brendanzab]

These are incomplete and complicate the API. I don't see them being fleshed out any time soon. Perhaps another library could take up the slack. Thoughts?

Proposed for removal:

• Aabb, Aabb2, Aabb3
• Bound
• Cylinder
• Frustum, FrustumPoints
• Intersect
• Line
• Ray
• Obb2, Obb3
• Plane
• Sphere

[kvark]

No problem. Will move somewhere else, since gfx_scene uses those.

[brendanzab]

@csherratt has his collision-rs library - maybe there?

I have mostly abandoned work on collision-rs, but I don't see a reason why we can't revive it and move these traits to it.

Not PR since it will destroy the history of collision-rs (github hates this) but I plan on merging https://github.com/csherratt/collision-rs/tree/merge_cgmath into master if you think it is a good place to live.

[brendanzab]

Looks good @csherratt! Let's merge #245 once your thing is published.

[brendanzab]

I've decided to merge the PR - we'll just hold off on publishing until the collision-rs is published

[brendanzab]

Reopening - we'll close this once @csherratt has done his thing.

Done! \o/