FS#2288 - Importer for data from Plesk control panel (first INCOMPLETE version, see bugtracker for status)

Bugfix: remoting lib field validation "ISINT" differed from tform validation and leads to 0 values treated as invalid
Bugfix: remoting lib did include_once instead of include at form definition files, that leads to malfunction when using multiple definition files at importing and actions like that

added tmp_vars for login + password_reset as replacement for hardcoded language non-neutral expressions

- Bugfix: changed "Return-Path: $form" to Return-Path: $from.

This option can be enabled under System > Server config and is named "Web folder protection".

Implemented: FS#560 - Add support for APS (Application Packaging Standard)

- Added Tipsy (http://onehackoranother.com/projects/jquery/tipsy/) so that one can create tooltips for additional explanations easily.

- 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.