Use auth.reminder.table config rather than hard-coding 'password_reminders'

The hard-coded table names cause problems on sites that don't use the conventional names (in this case, password_reminders). This issue was brought up in #148 and left at "If a pull request comes along I'd check it out."; well, here's that PR.

Sublime also cleaned up some trailing whitespace in the file - the only significant change is line 226.