Change to cylinder prim

This is more for variations on a prism.

A cylindr can be considered a special case of the prism shape, with 1 side. A box prim can be used to make a 4 sided prism. For other kinds of prism, you are out of luck unless you liek using excessive amounts of prims.

I propose that the cylinder prim have an additional part to it's definition - the number of sides.

1 - the original cylinder
2 - n/a (doesn't make sense)
3 - triangular prism
4 -
5 -
6 -
7 -
8 -

Except for "2", any number is theoretically valid, but higher numbers aren't visially distinguishable from a basic cylinder, and are probably best locked out.

This would allow for true prisms, and make it easy to make, for example, 50p coins.

One interesting thing to notice is, on viewers with low graphics settings, cylinders already do show up as hexagons, at least at some distance (at the very minimum settings, they always do). So this proposal ends up being a suggestion to add a Maximum Visible Sides setting, letting prims determine the limits to their own level of detail.

Just now for a minute, I was thinking that implementing this could allow the prims to be divided into just 3 types - prism, sphere, and loop. Then I realized that the texturing systems don't match up right at all for this. Cylinders only get one texture around the side, and should be kept that way. So the side texture would just wrap around all the given sides, kinda like the hollow texture (although that particular texture actually maps very oddly, and I wish something could be done about that).

A little bit of experimenting made me realise that the "prism" prim would be the best place to enable this flag, not the cylinder. That removes the need to have an empty placeholder for two sided prisms.

A key point here is that each face should be capable of having a different texture painted on it, which is not possible with the cylinder (but is with the prism prim).

I've suggested this before. I think most prims should have a "number of faces" slider.