Hhpy

- bugfixes
- flake8 fixes
- bump required python version to 3.8

- ds: fix naming errors
-- mpae -> maep
-- pae -> mpae
-- pae now shows as deprecated
- plotting:
-- improved animplot, added hue functionality

fix version number problem on pypi

hhpy.main
- bugfix: calling get_repr of BaseClass instances does not lead to permanently converting objects to string
hhpy.modelling
- bugfix: already having a pred column in your df doesn't lead to duplicate columns and thus errors when predicting

hhpy.main
-- added silentcopy
hhpy.modelling
-- switched deepcopy to silentcopy

another bugfix