Better sphinx theme

[jbowtie at amathaine.com]

I've been working on a better Sphinx theme for our HTML documents.
Feedback greatly desired.

Branch: https://code.launchpad.net/~jbowtie/bzr/better-sphinx-theme
Screenshot: http://imgur.com/7dpe5.png

Improvements:
* Top-level navigation matches Bazaar site
* Second-level navigation offers quick access to other guides
* Reading width is much more natural
* Ubuntu font (with rational font stack below it)
* Based on official Canonical branding guidelines
  - but will change to integrate visually with website when that is overhauled

Missing features:
* Color scheme follows Ubuntu branding instead of Bazaar branding -
need guidance here
* Bazaar logo and project name should be in upper right
* Breadcrumbs, previous/next links (currently hidden until I figure
out where they belong)
  - probably tertiary navigation
* Footer not formatted yet
* Some random elements still need work (tables, anchor colors)