Update travis to use new extras_require
Update travis to use new extras_require

bjodah/PyLaTeX,bjodah/PyLaTeX,ovaskevich/PyLaTeX,JelteF/PyLaTeX,sebastianhaas/PyLaTeX,votti/PyLaTeX,jendas1/PyLaTeX,jendas1/PyLaTeX,sebastianhaas/PyLaTeX,ovaskevich/PyLaTeX,votti/PyLaTeX,JelteF/PyLaTeX