Added several channels and HD channels

Added:
hr-fernsehen HD, MDR Sachsen HD, rbb Berlin HD, Einsfestival HD,
EinsPlus HD, tagesschau24 HD, ZDFneo HD, RTL (with 4 regional channels),
VOX, RTL II, Super RTL and n-tv

Merged 'NDR Niedersachsen' and 'MDR Niedersachsen HD' into one channel
with SD- and HD-url.

Also added german, english and some italian channel descriptions for the
'RTL-Group' channels.

Source:
http://grinch.itg-em.de/entertain/faq/allgemein/multicastadressliste/