Merge branch 'fixes_plot' into 'master'

Use matplotlib to save images

See merge request !37
4 jobs for master in 23 minutes and 55 seconds
Status Job ID Name Coverage
  Build
passed #171420
docker
build_linux_36

00:18:52

72.0%
passed #171423
macosx
build_macosx_36

00:03:21

failed #171421
macosx
build_macosx_36

00:00:01

 
  Deploy
passed #171422
docker
deploy_beta

00:01:42