Update to binary_c 2.1.3

Note there are minor updates to the API (see CHANGES or the release notes of this tag for details).

add new "overspin_algorithm" option to handle what happens
    when a star is spinning faster than it can
    
    currently there are two options:
    OVERSPIN_BSE transfers the excess angular momentum back to the orbit,
           so is conservative in that no mass or angular momentum is lost.
    
    OVERSPIN_MASSLOSS uses the rotationally_enhanced_mass_loss formalism
           given below to remove material which reduces the star's spin.
    
    Also removed the ROTATIONALLY_ENHANCED_MASS_LOSS compile define,
    because this functionality is now required always.

Added GAIAHRD logging flag for (currently, probably always, incomplete) Gaia logging.

Update stellar colours to use "magnitudes" rather than "colours" because this si more complete nomenclature.

Update to 2.1.1: a bug fix and cleanup release.

Binary_c 2.1 release.

Release V2.0pre28.