Pages: Upgade guide to QUnit 2.x

Fixes #86 

First draft for an upgrade guide. There are no links to this page, yet. There are layout issues, may need to port some CSS from jqueryui.com.

Would be good to get some feedback on the format. Also, am I missing something?
This applies to the all reporting callbacks, specifically...

I don't think you need to say “in alphabetic order” here because there are only seven of them.