Jonathan/password reset

Password reset functionality.

The login form has a link to a password reset form, where the user can enter an email address and ask for a password reset email to be sent. The email will contain a link to a password edit form.

Password reset requests are identified by a random unique hash that lasts for 2 hours.

To actually deploy this, we have to use a mailing service that integrates with Heroku. We also need to add the configuration parameters to config/environments/*.rb
config.action_mailer.default_url_options = { :host => "localhost:3000" }
with an appropriate value for 'host'.