 enable Py3 testing on travis
 enable Py3 testing on travis

CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,AntonioJBT/CGATPipeline_core,AntonioJBT/CGATPipeline_core,CGATOxford/CGATPipelines,CGATOxford/CGATPipelines,AntonioJBT/CGATPipeline_core,AntonioJBT/CGATPipeline_core