Index "owner" relationship in search correctly for Revisions

Summary:
The owners of a revision are only really the reviewers when the revision is in
NEEDS_REVIEW.

Also build a raw indexed document viewer so you can look at the index of a
document from the web interface.

Finally, reindex revisions when comments are added, not just when the revision
itself is edited.

Test Plan:
Toggled abandon/reclaim on a revision and verified the relationships indexed
properly.

Reviewed By: jungejason
Reviewers: aran, jungejason, tuomaspelkonen
CC: aran, epriestley, jungejason
Differential Revision: 470