Unit tests!

First batch of tests, using PHPUnit to test string functions.
gitattributes
Update deprecated notices in various files
Add PMs to user submenu
Add reply button to PMs
Paginate private messages

Add selectspec for counting messages
Add option for PM list page size
Prevent users sending private messages to themselves

Fixes #27.
Add pagination to blocked users page

Also create generic qa_db_selectspec_count function for modifying a
selectspec with COUNT(*).
Minor reorganisation of deprecated stuff
Fix user display on favorites page
Refactor qa-page-favorites
Fix headers warning on page plugins with custom output

Includes sitemap plugin
Extract favorites processing logic to functions
Allow 'footer' content at the end of a theme section
Allow limits in favorites selectspecs
Set up pagination for favorite questions, users and tags
Fix favorite pagination

And display of links on favorites main page
Refactor user-page controllers
Update routing to support Nginx

The Apache workaround broke some edge cases on Nginx