Fixed people widget
Test for None identity, not truthiness, in API responses. Fixes #205.

Any non-ok HTTP responses will be falsy, but we only want
to skip results that are actually None.
Merge remote-tracking branch 'origin/master' into metabar-moderation-tools
Merge pull request #206 from microcosm-cc/fix-expired-login

Test for None identity, not truthiness, in API responses. Fixes #205.
Merge remote-tracking branch 'origin/master' into metabar-moderation-tools
Add 'move' moderation action for items

This allows the moderator of a microcosm to move single items to a
different microcosm.

Display of the moderation menu is based on the 'moderator' permissions
flag.

Some edge cases (such as moving an item to a microcosm which is private)
are not yet handled.

Styling of the forms is still to be done, but they function.