New stories and acceptance tests.

This is fine for now, but for future reference let's look at splitting these up into separate acceptance tests.  So we would have tests like:

- clicking a valid "reset password" link
- clicking an invalid or expired "reset password" link

The reason to split them up like this is because each test must have its own "pass" or "fail" condition. If we group things too much, when they fail it will not be so clear which part is wrong.