Couple of fixes for editor notes

Fixed exceptions when note.user is None.

For TeamEditorNotes, input team/video in the constructor.  This allows
for the possibility of displaying notes for a different team than the
team that owns the TeamVideo.
Remove highlighted_qs from teams list

We aren't using it anymore.
Better way to query counts for teams list

Use subselects instead of annotate (which uses group by) to count
members.  This runs much faster.

Use a similar query to count videos, which avoids an extra query for
each team on the list.

Renamed member_count() to members_count().  I think it's nicer for the
name to have the same form as videos_count().
Avoid extra queries to check team membership for the teams index

Before we using an extra query for each team on the page.  Changed it
so we query team membership when we fetch the teams.
Use select_related() for the user activity page

This page was relatively fast, but adding this reduces the number of
queries tremendously.  On my dev machine it went from 102 to 30.
gh-1463 further reduces that to 10.
Speedup User dashboard queries

The old queries were very slow in a puzzling case: where they matched
0 Action objects.  I'm not really sure why that is, but using extra()
makes for more straightforward SQL and the queries perform better.
Use select_related() on the user dashboard page

This reduces the number of queries substantially.  The difference was
about 3-4 queries per Action item when I was testing.
Speedup the team invite admin page

user always should be a raw id field, since otherwise we are going to
do a query for all users in the system.
Don't try to use the vimeo API if there aren't settings

This fixes a few unittests.
More speedup for the team activity pages

Split the activity into 2 categories:
  - "videos" most activity on team videos
  - "team" members joining/leaving and team video deletion

Having to only select 1 or the other makes the queries much faster.
Also speed up the team videos query substantially with an extra()
call.
Merge pull request #1798 from pculture/speedup-team-activity2

More speedup for the team activity pages
Merge pull request #1799 from pculture/speedup-user-dashboard

Speedup user dashboard
Merge pull request #1800 from pculture/speedup-teams-list

Speedup teams list
Fixed bad attribute name
Merge pull request #1801 from pculture/notes-refactor

Couple of fixes for editor notes