Fix to a validation error

- regkey|value's validation was inversed only accepting incorrect entries
E-mailing system for site-admins

- site admins able to contact users by e-mail from within the system
- PGP encrypted where available
- Password reset with automatic temporary key generation
- all of the above options have a mass-email version where every user is
  contacted at once
- Potential new users can be contacted too (GPG key can be supplied)