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- Retained the compatibility with ``xarray`` 0.15 by removing the ``attrs`` flag.
- Added ``xarray_geomask`` function and made it a public function.
- More efficient handling of large GeoTiff responses by cropping the response before
converting it into a dataset.
- Added a new function called ``geo2polygon`` for converting and transforming
a polygon or bounding box into a Shapely's Polygon in the target CRS.