moved update scripts to tools directory
changed db layout for channels and programs

Programs now don't have a corresponding channel id, but a list of
channel ids, since esp. in reqional channels two (or more) might be
sending the same program at the same time.

Also the mapping of xmltv-data to fernsehnauten data isn't 1-1 any more;
display-name is name, sub-title is subtitle. Title, subtitle,
displayname, and desc are now strings instead of an array of arrays.

Lastly some minor enhancements to the update skript like the "--clear"
switch and cosmetic changes.