Revert r968, optimization in R_DrawSequentialPoly. Going to try a deeper change that uses the world drawing code for bmodels.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@978 af15c1b1-3010-417e-b628-4374ebc0bcbd
Remove R_DrawSequentialPoly and use texture chains for drawing brush models.

To make this work with the drawing order we use in gl_rmain (world excluding water, opaque ents, world water, transparent ents), I made each texture_t have two texture chains, one for world and one for bmodels. This way they can be cleared during entity drawing without having to regenerate the world ones.

Other than this the changes are mostly minor adjustments to the R_DrawTextureChains_* functions so they can work for things other than the world.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@979 af15c1b1-3010-417e-b628-4374ebc0bcbd
update README files to reflect further 0.85.10 changes so far.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@980 af15c1b1-3010-417e-b628-4374ebc0bcbd