Revamp the review request layout.
We've had the same look to the review request box since the dawn of

time. With 2.0, we're changing that to take up less vertical space,

to bring a little more consistency with some of the fields, and to

highlight the main content of the review request.
The main information (Summary, Description and Testing Done) are now

shown one after another, with the same font style used for the labels.
On the right-hand side is the list of fields we previously had between

Summary and Description. They're a single column now. This takes the

space that was often just left unused within the Description/Testing

Done fields (since those fields were often far wider than the contents).
Simplifying this into one column will also make it easier to lay out

fields provided by hooks.
The Screenshots, File Attachments and Issue Summary are displayed after

all the fields, as before. Their labels match the style of the Summary,

Description and Testing Done labels.
The Issue Summary table has been cleaned up a bit to have the filters

and the counters on the same row, reducing the amount of vertical space.

Played around with this in Chrome and in Firefox. It made much better

use of space, and didn't hide Testing Done when I had longer descriptions.
Made sure that the field contents could wrap and that that wouldn't

interfere with the inlineEditor (once the accompanying Djblets bug was

fixed).