Updating .travis.yml to get requirements from dev
Updating .travis.yml to get requirements from dev

It doesn't work to get the requirements from requirements.txt (symlink)
if the requirements file pointed to includes another file via the -r directive.

withrocks/arteria-core,arteria-project/arteria-core,johandahlberg/arteria-core,withrocks/arteria-core,johanherman/arteria-core