Changes to StationData: new string stationID (shortname)  to describe a station in short, stationName shall be used for long description of a station. changes required an adaptation within the plugins

Changes to ConfigReader: comments may appear anywhere (also after key value pairs or section names), everything after a '#' or ';' is disregarded.

PGMIO: small fix: xllcorner mixed up with yllcorner

FilterAlgorithms: extrapolate algorithm refined