Fix a link in the rb-site installer.

The link pointing to the site creation docs was pointing to an old page.
It's been updated to point to the correct URL for creating a site.

Reviewed at http://reviews.reviewboard.org/r/3619/
Merge branch 'release-1.6.x' into release-1.7.x
Merge branch 'release-1.7.x'
Prevent breakages when loading an old image file attachment comment.

ImageReviewUI introduced support for adding comments to a region of an
image file attachment, but any older comments loaded wouldn't have
region information. We assumed it was there, which caused us to break
with older comments. We now catch the error and just ignore that
particular comment when rendering the review UI.
Remove the sqlite installation docs.

Now that we require Python 2.5, sqlite is built in, so there's no need
to tell people how to install it.
Use the same font and size in both <pre> and <textarea>

By default, our textareas on MacOS X render in a non-monospaced font,
which makes our text entries transition very weirdly, and makes it more
of a pain to format text.

We now enforce that <pre> and <textarea> has the same font information.
Stop using the blesscss service.

This was a cool thing while it lasted, but all of the node.js packages have
changed their APIs (because apparently javascript developers don't understand
what "API" means) and it's currently so broken that I just stopped the app on
cloudfoundry. Since we have support for local lessc now, and will be requiring
node.js for other javascript compilation steps to build the egg, we might as
well just depend on it.

Testing done:
python setup.py bdist_egg release
Mention "To Me" column in the dashboard customization docs.

This is a very simple addition.
Reviewed at http://reviews.reviewboard.org/r/3624/
Add extension docs for URLHook, DashboardHook, and NavigationBarHook

This change adds entries to the extensions section of the codebase manual to
explain the usage of some of the basic hook points.

Testing done:
Ran `make html` in reviewboard/docs/codebase/
No error output from sphinx.
Rendered HTML pass visual inspection.

Reviewed at http://reviews.reviewboard.org/r/3617/
Support the p4api 12.2.

This adds support for p4api 12.2. The main differences that affect us is
that P4Error was renamed to P4Exception, and there's a different error
when we can't reach a server (for repository not found).

This change adds compatibility for the new API, which we'll be able to
switch to later, hopefully successfully. It also keeps compatibility
with the old API for existing users.
Update our settings documentation.

This updates our settings documentation to cover all the changes that
were made in 1.7 (and even some that we made late into 1.6). That
includes new settings like the cache fields and max diff size.

The optimization page also got some changes. It was referencing
CACHE_BACKEND, which is gone, and so was updated to point to the Cache
Settings. While I was there, I added an important note to the web server
scale-out docs.
Added some overview docs on extensions and management.

These docs are somewhat basic, but give a summary of what extensions
are, some basic info on installing them, and what to expect on the
Extensions page.

We can probably fill these out more later, but there's not really a ton
to say at this point in time anyway.
Replace the Windows installation docs.

The Windows installation docs are gone now. In its place is a note about
why we don't support Windows, and some alternatives. These include
trying it yourself anyway based on older docs (and a mention that we
don't support it), using Linux (optionally in a VM), and using
RBCommmons.

Let's see how long until people get mad at us.
Merge branch 'release-1.7.x'