[wp-docs] Codex pages relating to theme development

[Lance Willett]

> http://codex.wordpress.org/WPMU_Theme_Compatibility
>
> While this page in particular is mostly obsolete, it does raise some points
> for people who release themes that may be used in a network of sites.
>
> The whol page can go as the title is misleading. :D theme devs need to be
> aware of things like the edit_themes capped used for accessing theme options
> pages will prevent blog admins in a network from seeing those menus. That's
> pretty much it.

Great, thanks for the reminder, Andrea.

-Lance