Lots of changes for version 0.4

* No longer requires a personal FTP account, since it now uses the
public FTP service
* fixed a bug in query(), where all returned data was for hard  coded
station_id 2667
* New data attributes in the category „solar“ have been added, although
their meaning is unclear.
* Station data is read from a different source now, which returns much
more stations.
* -v option for verbose command line client output added