(Bug 2165) Fix editing of community members

Accidentally made it so that we thought the old state of the member/etc
checkboxes was always true, which meant on save any unchecked checkbox
would trigger a message, any newly checked checkbox would have no effect
(because we assumed that they were already a member, etc)

Also removes a doubled instance of checkbox_nested.
(Bug 2165) Fix deselecting an entire column

Selecting an entire column always worked.

Deselecting by clicking on just the select-all checkbox worked, but
clicking on the label didn't.
(Bug 5073) Don't use position:absolute for userpic on small screens
Merge pull request #651 from afuna/members-edit-bugfix-bug2165

(Bug 2165, 5073) Fix various foundation / converted pages issues