Improved Channel.MATCH regex for GEO channel support

GEO and Virgo channels don't follow the same conventions as LIGO, but should be handled just the same. This PR modifies the Channel.MATCH regular expression specifically to allow dash-delimited channel-name components other than the first division, and to optional match a trailing -[a-z]+ string as the trend type (GEO uses -min rather than .min, for example).

This might break if it turns out there are channels with a dash-delimited lowercase component that isn't the trend type, but I haven't come across an example of that to date.