update Travis CI test build with python 2.7, 3.8 - gcc 7, 8, 9
update Travis CI
test build with python 2.7, 3.8 - gcc 7, 8, 9

LraiZer/RadiotimesXmltvEmulator,LraiZer/RadiotimesXmltvEmulator,LraiZer/RadiotimesXmltvEmulator