Add some presentation improvements for configforms.

Review Request #5696 — Created April 10, 2014 and submitted — Latest diff uploaded

Information

Djblets
master
463b8ba...

Reviewers

This adds a new class used for the descriptions at the top of a config
form, used to provide decent spacing when using one or more paragraphs.

It also shows a spinner when the item indicates it's communicating with
the server, and hides it when it's finished communicating.

Made use of these changes in RBCommons, and saw what I expected.