Don't deal with unused files in a parent diff.

When uploading a diff with a parent diff, it's very common to have files
that are in the parent diff that are not in the actual diff going up for
review. This is especially true for large merge branches, or when some
incorrect parent diffs are put up (wrong parameters passed to
post-review/rbt post).

Each unused file gets checked against the repository and then then
thrown away. This is pointless.

We now ignore every file in a parent diff that doesn't have a matching
diff in the actual diff file.
Fix issues with the borders/corners around datagrids.

On the datagrids (all but the dashboard), the title header didn't have
rounded corners, making the background stick out just a bit.

On the bottom of the datagrid, the last item did the same thing. The
last entry now should always have rounded corners.

There was a small issue with the padding at the bottom of the box for
datagrids that made the rounding at the bottom look wrong. This was 1px
padding that IE needed. We now target IE specifically for that padding
with a little hack.
Add support for registered GitHub OAuth applications.

Registered GitHub OAuth applications have the added benefits of central
revocation of a key and higher rate limits. While it's not possible for
us to turn this on for every installation out there (since sharing a
client secret is a very bad idea), those who need it can register their
own application entry and set it up with Review Board.

This is a pretty advanced feature, so there's no UI-side configuration
for this. Those who need it are expected to set the
settings.GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET keys.
Fix review request ID in email subjects.

We were using the id in email subjects instead of display_id. Very simple fix.

Reviewed at http://reviews.reviewboard.org/r/4032/