title: devise: "Reset password token is invalid" message
body: <p>I'm using devise 2.0.4 and cannot find where the "<strong>Reset password token is invalid</strong>" message is defined.  I would have thought it was in the locales YAML file but it is not. I've also searched the gem source to no avail, which leads me to think that it must be constructed at run time.  In the <strong>devise_error_messages!</strong> method I see that it must be defined as one of the <strong>full_messages</strong> for the resource, but being somewhat of a rails newbie I'm not sure where to look for that.</p>