Version 2.1: make Joomla 1.5 work, straighten out language files, add German

Makefile

elements/rklabel.php

language/de-DE/de-DE.plg_vmshipment_rules_shipping.ini

language/de-DE/de-DE.plg_vmshipment_rules_shipping.sys.ini

...ge/de-DE/de-DE.plg_vmshipment_rules_shipping_advanced.ini

...e-DE/de-DE.plg_vmshipment_rules_shipping_advanced.sys.ini

language/de-DE/index.html

language/en-GB/en-GB.plg_vmshipment_rules_shipping.ini

language/en-GB/en-GB.plg_vmshipment_rules_shipping.sys.ini

rules_shipping.xml

rules_shipping_advanced.xml