Create test suite

[ArthurN]

Test cases:

1. Should not download non text/html content
2. Should not allow circular redirects
3. Should allow relative redirects
4. Should handle bad title/favicon/description HTML
5. Should follow normal redirects to the end
6. Should work on 't.co' (which does different things depending on user-agent)
7. Should not allow circular redirects when next redirect is relative URL (http://t.co/UxIS7vV)