Recursive Categories module for OXID eShop 4.7.7 (and possibly other versions)

!! Development version, don't use in production !!
TODO: Bugfixing, check session filters (possibly won't work yet).

This module changes the default OXID eShop behaviour to list products of a
chosen category including the products in its subcategories.

The module is based on ideas posted in the OXID Community Forum (german):
http://forum.oxid-esales.com/showthread.php?t=16310

Contributons welcomed. Send me an email if this module works for eShop versions
not listed here.

Author:
Christian Neumann <cneumann@datenkarussell.de>