data storage and plotting of realtime rdahmm

Since the present modifications to the real-time RDAHMM service is just an initial version that is not fully correct, we need to store all received data for possible remodeling and evaluation purposes in the future. We now use one file to save one day's input data for one station. And all data for all stations is stored in a directory structure like this: "histParentDir/stationName/yyyy/mm/statioName_yyyy-mm-dd.dat".

For plotting, we'll first do tests with the existing plotting script, which plots with lines instead of points. We'll switch to points later.