Support Elite Force MP rendering primitives

[zturtleman]

Thilo's Elite Force patch for ioq3 adds several new rendering primitives, most of which are in JK2/JA too I think.

I'd like to make it possible to add them in cgame. Probably requires engine changes before this can happen. Need option to force two sided cull, and generalize other parts that use backEnd.viewParms.or.origin (so they can work in mirrors and portals).

Might be tempted to add a patch shader with the correct cull types...

Initial work on moving Q3 rendering primitives was done in issue #135.