Merge atdm-nightly to 'develop' to avoid future merge commits the other way (3/29/2019)

Created by: bartlettroscoe

Had to merge the branch from PR #4750 directly to atdm-nightly to get around constant crashing of the PR builds (that had nothing to do with the changes on the branch other than they triggered the enable of all the packages). The PR #4750 since merged (but after the auto-update of 'atdm-nightly' last night at 10 PM MDT). This PR merges the other way so that future updates from 'develop' to 'atdm-nightly' will be fast-forward merges.

It is important to merge 'atdm-nightly' to 'develop' so that future merges from 'develop' to 'nightly' will be fast-forward merges. That is important so that the SHA1s shown on CDash will be SHA1s in the 'develop' branch. We don't want 'atdm-nightly' to be a release of Trilinos, we just want it to ensure that the same version of Trilinos is tested each testing day.

However, if the Trilinos PR tester continues to have problems we may need to update the 'atdm-nightly' branch more in the future (but we would like to avoid that) and then have the ATDM APPs pull from 'atdm-nightly' instead of 'develop' (but since that bypasses PR testing builds that would not be good to do in general).