Geoenrich

New functions:
- New function to estimate download size before starting enrichment.

Bug fixes:
- Fixed an error in load\_areas\_file.

New functions:
- Possibility to specify colormap when exporting png files.
- Possibility to export data as resized and normalized numpy arrays.
- Possibility to provide enrichment file to retrieve_data to reduce processing time.

Bug fixes:
- Fixed an error that occurred when data is not available for all occurrences of the dataset.
- Fixed an error when trying to export a png file with no data.

Bug fixes:
- Fixed an error that was occurring when time or depth have a non-standard name in the source dataset.
- Fixed an error due to time dimension not being flagged as 'Unlimited'. New time points could not be downloaded if data points were more recent than the creation of the local netcdf file.

Bug fixes:
- Fixed errors in *dataloader.import_occurrences_csv*.
- Removed an empty line in catalog.csv that was causing errors.

New functions:
- Arbitrary areas can be enriched in addition to buffers around occurrences.
- Possibility to sample down remote data to achieve faster enrichment on large areas.
- Added possibility to calculate variables: EKE + derivatives
- Added documentation and tutorial about using the package with R
- Added possibility to export data as .png files.
- Modified metadata structure to handle several enrichments with different buffers on the same dataset and variable.