Annex the Admin Toolbox, re-style, add username, simplify

Fixes #853 and improves Admin Toolbox in general.

Remove the old Admin Toolbox styles from included themes.

The IDs have been changed, so old themes with toolbox styles should not have a problem.
Merge pull request #860 from zenphoto/admin_toolbox_853

Annex the Admin Toolbox, re-style, add username, simplify