Issue #1022404 by Berdir, te-brian: Added drag and drop sorting for list display fields and replaced header theme functions with a hook.

#1011984 by Berdir: Fixed 7004 update function depends on privatemsg_filter 7001 if it is not enabled.

#432084 by nbz, Berdir | yaz085, Liliplanet: Added option to display new message indication block without new messages

#555016 by Berdir | neriweaver, trupal218, BenK, nbz, archard, nilsja, kriskd, Liliplanet, yaz085, litwol, Feet, jaron: Added recipient types, allowing to send messages to roles and other recipient groups.

#520390 by Berdir | drupup: Added option to configure the display of the send message to themself link (D7 Port).

#341370 by Berdir, nbz | sbydrupal, mrgoltra: Added 'Send msg to author' link to selected node types (D7 Port).

#404044 by rmjiv | Berdir, nbz: Added setting that allows users to disable private messages (D7 Port).

#490650 by litwol, JirkaRybka, nbz, Berdir, Liam McDermott: Message to oneself AND aditional recipients remains as unread forever. This patch fixes this behavior moving forward as well as providing update hook to update old messages that were affected by this issue.

.module: Remove subscription (and mail_edit) code which has been moved to pm_subscriptions.
.info: Remove dependency on subscriptions and mail_edit modules.
.install: Remove mail_edit queries. Roll back user table alteration. Roll back triggers update.

#182369: Add variables column in _install; Add update.

As this is a development branch, no rollback update path will be provided for testers. See issues in question for more information.