Request: Add optional parameters for rounding and capping

[interob]

Request: introduce parameters for rounding and capping upon grid export (modis/window.py), Explained in more detail below:

Rounding: as the value array is retrieved from HDF(s) here...

modape/modape/modis/window.py

Line 224 in 74e3805

value_array = self.get_array(dataset, ix, self.dt_gdal[1])

... next it would be to round values to an exponent of 10 (e.g. 2 => 10^2 = 100; rounding 10466 would become 10500)

Capping: all values in the retrieved array that are below or above the provided minimum or maximum respectively are set to nodata

[interob]

Remark: let's stay away from scaling by applying some factor (1/10000 typically) as this would require a change of output datatype

[valpesendorfer]

implemented with #104