In .travis.yml: * Use caching for the "gitignore" job. * Try using the "bionic" linux distro instead of the default.
In .travis.yml:
* Use caching for the "gitignore" job.
* Try using the "bionic" linux distro instead of the default.

mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem