20210602: 

Added a sample stationxml with FIR filters. This file was obtained by cut and paste from the following webpage:
https://service.iris.edu/fdsnws/station/1/query?net=BK&sta=PKD&loc=--&cha=LQ2,LQ3,LT1,LT2&starttime=2007-03-14T14:20:00&endtime=2008-08-26T00:00:00&level=response&format=xml&includecomments=true&nodata=404a

Added a sample stationxml with FAP filter. This file was cut and paste from the following webpage:
https://service.iris.edu/fdsnwsbeta/station/1/query?net=EM&sta=FL001&cha=MFN&level=response&format=xml&includecomments=true&nodata=404
