Update docs around testing table classes.
Update controller testing docs.

Remove sections related to redirect(). We don't need to explictly call
out the return requirements as that should be part of the controller
docs.

Remove section on staticExpects() it is deprecated in PHPUnit and will
probably be removed if it hasn't been already.
Update testing docs.

* Fix mistakes and formatting issues.
Feedback from review.
Merge pull request #1317 from cakephp/update-testing

Update testing