Write meteo data: OK

Read station data: implemented.
In this routine, the user must choose (= comment/uncomment) he we write every station or if we use the given date to filter which station are written

Notice: have to check how dateStart and dateEnd are chosen if we provide a single date (eg in meteo_reading.cc)... Now it takes "date - 6 hours" --> "date + 15 days - 6 hours"