[12gevmoller_sim] [JeffersonLab/remoll] 9acada: Save pdf files instead of png to get past #226

[Wouter Deconinck]

  Branch: refs/heads/bugfix-write-pdfs-in-travis
  Home:   https://gcc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FJeffersonLab%2Fremoll&data=02%7C01%7C12gevmoller_sim%40jlab.org%7C0629b9e01cc24841d35008d6abba35e4%7Cb4d7ee1f4fb34f0690372b5b522042ab%7C1%7C1%7C636885213589792795&sdata=jdsAelOW%2BIJTHyvQFfLL%2BkSD2ZZ7ltHD2K7LJGYMTjM%3D&reserved=0
  Commit: 9acada73651df73ec10a784615c0446fd1c8fbdb
      https://gcc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FJeffersonLab%2Fremoll%2Fcommit%2F9acada73651df73ec10a784615c0446fd1c8fbdb&data=02%7C01%7C12gevmoller_sim%40jlab.org%7C0629b9e01cc24841d35008d6abba35e4%7Cb4d7ee1f4fb34f0690372b5b522042ab%7C1%7C1%7C636885213589802770&sdata=OFJmPnP2of7lJWxQOM2m76Z62rEdjYMIc2x%2F5skG7cM%3D&reserved=0
  Author: Wouter Deconinck <wdconinc at gmail.com>
  Date:   2019-03-18 (Mon, 18 Mar 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Save pdf files instead of png to get past #226

Not a solution for #226, won't be merged into develop.