Begin moving to a new site style.

This is a refinement on the style we've had for years. The largish
page header and navigation bar have been slimmed down to a sleek two row
navigation bar at the top of the page, giving lots of room for the rest
of the page.

The search bar has moved to the top, beside the new account and support
dropdowns. The account dropdown links to preferences, log out, and the
administration UI (for admins). The support dropdown links to docs and
the bug reports.

There's also some style tweaks to the dashboard to tidy it up just a
little bit. These changes are more subtle.
Give the review request action bar a whole row, and lighten the colors.

The review request action bar no longer shares a row with the summary
line. The colors are less subtle, and the background removed. It blends
in a bit better now with the review request box.
Standardize definitions for some CSS properties.

This replaces some browser-specific CSS properties with lesscss macros
we have, and adds some definitions for some colors we use throughout the
CSS.
Add some subtle rounding and shadows to certain boxes.

This changes some of the core boxes to be slightly rounded and to have
very subtle shadows. It doesn't look overused, and adds a nice cuteness
to the UI.
Standardize the action bar color, and right-align it.

This removes the visual distinction between primary and secondary
actions. There's not much reason to really color these differently.
There's now a nice, seamless look across all actions.

The action bar has also been right-aligned, in order to match 1.6.x a
bit closer, so that muscle memory doesn't become an issue. In
particular, we want "View Diff" to be in the same location.
Fix the headbar menu z-order and Ship It border radius.

The headbar menu no longer sits below other UI elements.

The Ship It border is now rounded, rather than making the review box
have a sharp corner.
Tweak and update the admin UI style.

The admin UI style has been updated to match the new Review Board UI
style. It has the new header bar (though in a yellowish color to signify
that it's the admin UI) and bits of the UI match the RB color scheme and
images.

The admin login page has been replaced with our standard login page.
This reduces complexity quite a bit.

Rather than fight the Django admin CSS files, we now ship our own
version of their admin.css. While we may have to update it as Django
updates theirs, it's overall less painful.
Add a nice rounding to the admin UI elements.

This helps bring it in line with RB's rounding. It gives a softer, nicer
feel to the admin UI.
Combine the Add/Update actions into an Update dropdown menu.

The Add/Update File/Screenshot/Diff menu items are now under an Update
menu. This is a bit nicer, and condenses the action bar a bit.

As part of this, I've removed the <img> for the dropdown arrow and made
the CSS take care of that. That required some shuffling of which part of
the items had background colors. It's now the <li>, not the <a>.
Move the reply banner below the box headers on reviews.

The reply banner was being shown above the expand/collapse button, name,
and date on reviews. This felt a big wrong, and made the UI jump a bit.
Now it's positioned below this header and above the content.
Merge branch 'new-admin-styles'