[wp-docs] theme compatibility

[mrmist]

Sorry to drag up this old chestnut again, but I've just deleted theme 
compatibility / 3.0 which someone created last night.  I'm pretty sure 
we agreed to stop maintaining this stuff, which is essentially SEO juice 
for those who happen to add their sites to the list, rather than being 
anything fundamentally useful. Plus we have both plugin and theme 
browsers now.

Is there a reason why we would allow / 3.0 into there?  Also should we 
delete the historical pages for these?  We have compatibility stuff 
going back to version 2.1 at the moment, we don't tend to keep 
historical info anywhere else in the Codex.
-- 
mrmist