Flattentool

Fixed

- Rename `_get_column_letter` import to `get_colunmn_letter` for compatibility
with latest openpyxl
https://github.com/OpenDataServices/flatten-tool/issues/443

Fixed

- Ignore null characters in the input CSV file
https://github.com/OpenDataServices/flatten-tool/pull/435

Changed

- New "geo" optional python dependency and some existing python dependencies moved to it.
If you were using this functionality before, you'll need to start installing "geo" to get same behaviour.
https://github.com/OpenDataServices/flatten-tool/issues/424
https://github.com/OpenDataServices/flatten-tool/pull/433

Changed

- Flatten & Create Template: Previously, CSV filenames were truncated to 31 characters, which is the maximum length of a sheet name in Excel.
Now allow CSV filenames of any length and only truncate sheet names when the output format is XLSX or ODS.
https://github.com/OpenDataServices/flatten-tool/pull/428

Fixed

- flatten --sheet-prefix option does not work in ODS files https://github.com/OpenDataServices/flatten-tool/issues/430

Added

- Generate templates that are correct for WKT <-> geojson conversion

Added

- WKT <-> geojson conversion for flattening and unflattening, behind an optional flag https://github.com/OpenDataServices/flatten-tool/issues/419

Removed

- We no longer support Python 3.6