Adds docs for HOST_THEMES configuration.
Made a few grammatical fixes.
Removed a caveat that can go in the PR comments.
Better defaults for non-english language codes.
Added setting ADMIN_MENU_COLLAPSED for controlling admin side-nav behaviour.
Remove dashboard link from admin menu - replace with cliackable Mezzanine title.
Highlight selected item in admin nav.
Move site/lang drop-downs into top nav bar.
Bigger buttons throughout admin
Merge
regen settings docs
Move multi-site docs into new section.