Update torus primitive

[slimbuck]

This PR:

• adds support for torus to getShapePrimitive
• calculates torus area
• sets the second set of UVs on torus prim (like the others)

! Make torus great again !

[mvaligursky]

Nice! I look forward seeing it in the Editor in the future.

[willeastcott]

I'm cool with this. Some notes:

1. One of the reasons torus was never exposed to the Editor is that there's no torus collision shape available. And it seemed nice to keep the visual and physics list of shapes the same.
2. If we want to add more procedural shapes in the future, where should they live? Do we want the core library bloated with torus knots and teapots....or should shapes be in some external sets of library scripts?

[LeXXik]

Just to note, that torus could collide with other dynamic mesh, if it were created as convex hull mesh. Currently all mesh colliders use btBvhTriangleMeshShape, which is optimized in Bullet for static meshes. Convex hulls are more expensive, but they can collide with each other even being dynamic. There was an ancient issue about it: #123 (still open miraculously)

I would vote for keeping them as external, like the post effects. This would allow adding teapots and whatnot.