pfdf 1.1.0

This release add the following major features to pfdf:
* Comprehensive documentation
* Raster preprocessing
* Parallelization options when locating outlet basins
* Windowed raster reading

The release also provides minor improvements, as follows:
* Raster data/nodata masks,
* Improved model broadcasting options,
* The Segments.in_mask and Segments.in_perimeter methods