Function to retrieve statistics from a field
field_stats(values, ncfile, varn)
[values]= [stats],[fillVals],[countVals]
[stats]: kind of statistics
'full': all statistics given variable
[fillVals]: ':' list of _fillValues ('None' for any)
[countVals]: ':' list of Values@cond to use to count conditions ('None' for any)
[ncfile]= name of the netCDF file to use
[varn]= variable name to use ('all' for all variables)
$ python ${pyHOME}/nc_var.py -o field_stats -S 'full,None,None' -f startphy.nc -v all