Fieldgroup help text and description are not shown in tabs with cck fieldgroup tabs style

This patch allows to show the fieldgroup help-text and fieldgroup description in the tab.

This way, when editing/creating/viewing a node which content type has cck fieldgroup tabs, you get the fieldgroup help text and the fieldgroup description for the group with tab style is shown before the content.

As there is no description field in the Tabs API, it is needed that cck fieldgroup tabs add the help text/description to the content.
This help-text and description are with an specific css class in order to allow styling it differently from the tab content.