Definition of function get_data()

This is a very first draft of the code to get the values of the variable "var" for the entire time record of that specific file (http://stream.princeton.edu:8080/opendap/vic_conus_3km/2009/200906/VIC_Output_M03_CONUS_20090601.nc).
It would work just with this specific dataset, because the code to get the data depends on the structure of the data. NetCDF files may have different structures...
NoData should be managed in some way, maybe replacing them with a specific value or passed to make_json and it will manage them...