First attempt at fixing Travis CI
First attempt at fixing Travis CI

pythia-project/pythia,pythia-project/pythia,pythia-project/pythia,pythia-project/pythia-core,pythia-project/pythia-core,pythia-project/pythia,pythia-project/pythia-core,pythia-project/pythia-core,pythia-project/pythia,pythia-project/pythia,pythia-project/pythia-core,pythia-project/pythia-core