#895808 by oadaeh: added the option for specifying what the opt out message is that is displayed to users.

Fixed a problem for when the user is not a member of any roles other than authenticated and he or she edits his or her account.

#394318 by ProfStein: Fixed a bug where single categories were not being selected by default. Also, added some missing variables in the uninstall, and tweaked a SQL statement.

Commiting some changes from last year: modified error messages, and changed category opt-out options.

248193 by Ashford: Changed the way HTML and plain text messages are created, including taking into account the Mime Mail module. Changed a variable name. A couple of other minor things.