add colorama to tox config, because that improves the color output
add colorama to tox config, because that improves the color output

dwillmer/jedi,mfussenegger/jedi,dwillmer/jedi,WoLpH/jedi,mfussenegger/jedi,tjwei/jedi,WoLpH/jedi,flurischt/jedi,jonashaag/jedi,tjwei/jedi,flurischt/jedi,jonashaag/jedi