New cyli, cylo and ring primitives.

[Travis Cobbs]

It is not a restriction but a suggession: "In general, three decimal places are sufficient for parts". All the parts I made for years have 5 digits transformation matrices, because I got too many problems with just 3. Even 4 causes problems.

Good point, but I still think the parts restrictions spec should be updated to reflect that. If more precision is required for matrices, then the "In general" sentence is misleading at best, and wrong at worst.