fixed serialisation of epsr in Potential::Coulomb::to_json
fixed serialisation of epsr in Potential::Coulomb::to_json

mlund/faunus,mlund/faunus,gitesei/faunus,gitesei/faunus,bjornstenqvist/faunus,gitesei/faunus,bjornstenqvist/faunus,bjornstenqvist/faunus,mlund/faunus