add hooks for info pages after install and upgrade

pages are just stubs for now
fix broken link to addon sdk installation info
Recommend using development version of addon sdk
Explicitly detect Australis
First run page chosen based on FF version
draft first run page
stylish list numbers
light blue background
move styles to external file
Reuse OpenSans.css for first run page
balance list number's font size
blank target on first run page's links

This makes the links open in a new tab. I think this is helpful for people who
might click a link, and then not know how to get back to the first run page.
pad the bottom of the page for balance
specific wording for contact methods
copy first run page and tweak for australis
comment out upgrade page pop-up until we have one
Merge branch 'master' into feature/first-run

Conflicts:
	lib/main.js
use wordmark logo with mozilla branding
change styles (darker theme) for new logo
Merge pull request #517 from mozilla/feature/first-run

Feature/first run