`get_publicdata()` & `get_measure()`: allow `verbose = TRUE`

`message()` actual query executed for debugging reasons

e.g.

> https://api.netatmo.com/api/getpublicdata?lat_ne=51.53&lon_ne=7.13&lat_sw=51.34&lon_sw=6.89&required_data=temperature&filter=false

instead of

> /getpublicdata: Fetching stations from the following area: 6.89, 51.34, 7.13, 51.53 ...