Add missing files for the manual.

The web API docs were complaining about some missing files, which
.gitignore was hiding from me. This should fix the docs builds.
Escape text for markdown when updating from pending or committed changes.

When updating from a pending changelist (perforce) or a committed change
description (svn or git), we may need to escape the description and/or testing
done fields. This adds the relevant calls to do so.

Testing done: Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/5006/