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- moved link to private messages to the user block.
- added link to send messages to user info pages.
- some XHTML changes.
- user system has changed from $user->id to $user->uid.

- messages splitted in pages, setting for "how many messages per page"
- privatemsg_get_link() to add theme support; see INSTALL
- throttle to limit abuse; setting in admin for max send rate
- checked sql indexing and added index to recipient
- save sender ip address
- code cleanup (less global variables, use drupal form functions, better date format in list, comply to coding standards)
- minor cosmetic changes