Add a stronger warning about fastcgi.

Apparently fastcgi is also responsible for the API issues with LDAP auth. Since
there's not much we can do about this from our side, I've changed the docs to
just more heavily recommind mod_wsgi.

See issue 2322 for more details.
Handle "(revision )" for source files.

Our svn revision parsing code already had a special case for the pretty wacky
"(revision )", but it only worked when this was seen for the new revision. If
we got this for the source revision, we'd hit various errors. I've changed the
logic to report this as PRE_CREATION, which shouldn't break the old IntelliJ
diffs but should work for whatever wonky tool was used for bug 2632.

Testing done: Ran unit tests.
Fix PEP-8 issues in accounts/ and admin/

This change fixes up most of the issues found by the pep8 tool. The ones that I
left where where we had mapping tables that were formatted for readability.

Reviewed at https://reviews.reviewboard.org/r/4412/
Add infinite scroll for commits in the new review request UI.

This change makes it so scrolling to within 50px of the bottom of the list of
commits in the New Review Request page will automatically load another page.
This shows the little "Loading..." spinner at the top, but is otherwise pretty
seamless.

Testing done:
- Loaded many pages of commits.
- Connected a repo with only a small number of commits, and saw that it stopped
  loading once I hit the bottom.

Reviewed at https://reviews.reviewboard.org/r/4411/