version 2.0 compatible with CMD_3.8

What's Changed

• Updated the interface to the new PADOVA website (i.e. >=3.8) [minor changes in the form format from 3.7]
• New function get_isochrone does all the slices directly (combines get_Z_isochrones, get_t_isochrones, and get_one_isochrone which are now deprecated.)
• get_isochrone handles ages, log ages, Z and [M/H] as inputs (see documentation).
• Most of the code has been rewritten to be more robust and easier to maintain. In particular the parsing of the online form has been improved.
• Many integration tests to keep checking the package interface.
• The output format is now a pandas.DataFrame instead of the internal format. (though previous aliases of columns are no more available)
• added resample_evolution_phase function to resample the label into a continuous evolution phase instead of discrete labels.
• added interpolate.QuickInterpolator to quickly interpolate isochrones over (logage, MH, evolution phase)
• Documentation has been updated and (hopefully) improved.

Full Changelog: https://github.com/mfouesneau/ezpadova/commits/v2.0