Mikeio

* Improved documentation
* Minor tweaking
* Use released version of mikecore

First release of MIKEIO based on Python version of [mikecore](https://github.com/DHI/mikecore-python).

Benefits:
* Runs on Windows & Linux
* No need for [Python.NET](https://github.com/pythonnet/pythonnet)

Minor updates and consistency improvements.

This will be the last release based on the .NET SDK and thus Windows only.

Next release (0.7) will be based on [mikecore](https://github.com/DHI/mikecore-python) and run on both Windows and Linux

The Dfsu class has two new methods
- to_dfs2 thanks to georgebv
- extract_surface_elevation_from_3d

* Dataset improvements
* Progress bars (optional)
* Dfs3 improvements
* Misc features

* Dataset have information on data value type (e.g. Instantaneous, Accumulated)
* Finalization of Dfsu - Grid2D interpolation
* Plot Dfsu vertical profiles
* Updated binaries from MIKE 2021
* Bugfixes
- Handle delete values in the generic module