- Clean up some raw output

less code++

#14591, User.module links for blocked/non-existant accounts + menu 403/404 issue, patch by Steven and merlinofchaos

  + Conversion to _validate + _submit model..
  + Split replaced by explode - faster
  + Fixed typos: Recipient
  + Fixed weight defaulting to -10
  + Popped mail subject formatting into a t()
  + Popped '--' formatting into a t()
  + Does a lot of documentation fixing/rewriting.
  + Renamed contact_user_mail form functions to contact_mail_user for consistency.
  + ...

- Patch #40532 by wtanaka: use longblog for data in the cache.  Is reported to fix utf-8 problems and improves consistency with PostgreSQL.

- Patch #28062 by Souvent22: make it possible to assign weights to contact form categories and fixed some small glitches.

  to validate other form submissions, not just comments. Two new functions
  are introduced, form_token() and form_validate(). The first function uses
  a private key and a public key to set a token in a hidden field. The second
  function validates the token. The comment and contect module are updated to
  use these functions.

  + made it possible to specify a subject when submitting a message on the contact form.
  + fixed some bugs/glitches.

  TODO: document the defaults in the PHPdoc comments.