* add yapf and isort to travis
* minor formatting
* remove blank lines
* skip unit tests for progressbar when python2
* update travis to ubuntu 16.04
* use a newer version ffmpeg
* add -y to add-apt-repository
* Make latest symlink relative. Add tests
* Skip test_save_checkpoint in the absense of torch
* Fix pep8 in test_runner
* Import runner only if torch import has succeeded