Note to all contributors: please use utf-8 encoding in files!

- Added check so that the client password isn't inserted into the message (for security reasons).

- Added circle access control so that 1) a reseller can create circles that contain only his clients, not all clients, and 2) a reseller can send messages only to his own circles instead of all circles.

- Added group (we call groups "circles" so that users don't mix them up with user groups) feature to client messaging section so that messages can be sent to either all clients/resellers or to groups of clients/resellers. TODO: add circle access control so that 1) a reseller can create circles that contain only his clients, not all clients, and 2) a reseller can send messages only to his own circles instead of all circles.

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- Random password length: by default, generated passwords will have a length between 10 and 15 characters (instead of a fixed length of 10 characters).

Merged revisions 3049-3051,3053-3054,3058,3070,3074-3077,3082,3086-3088,3091-3092,3094-3095 from stable branch.

  @param  -> session_id
  @return -> Array of all Client IDs on server

Splitted the remote function permission array for the remote user form into separate config files. The new remote.conf.php files are located in the lib folder of the modules.