Hydroeval

General:
- drop support for Python 2.7.x

API changes:
- `evaluator` now supports any array-like object, e.g. `numpy.array`, `list`

Tests:
- add `unittest` test suite to check that new commits do not change results
- add `doctest` tests to check that the API as presented in the docs is working
- add GitHub workflow

Documentation:
- add a documentation website generated with Sphinx

Post-release of HydroEval v0.0.2 to trigger DOI generation with zenodo.

Post release to correct minor mistake in setup.py that was not using README.md for the long description of the package.

Bug fixes:
* adds relative imports for non-parametric KGE

Documentation fixes:
* updates the tutorial notebook to correct typos

* Re-defines axis=0 as default array orientation
* Adds non-parametric version of KGE
* Corrects mistake in bounded original and modified KGE

Initial Version of HydroEval