Create Script to Snapshot Compadre into Trilinos

[jmgate]

Part of #164.

The preferred way of snapshotting a package into Trilinos is via the snapshot-dir.py tool from TriBITS. That script uses rsync to do a complete copy of the source directory into the destination directory. That's not exactly what we want for Compadre because we want to be able to exclude certain files/directories (e.g., kokkos, python) from the snapshot. As such, we'll need to write our own script to do the snapshotting, but it can leverage the snapshot-dir.py script under the hood.

[jmgate]

Note that I'll be pausing work on #171 to work on this issue, because this will be easier to do when working remotely. That said, I expect to get back to #171 soon, likely well before we're allowed to return to work.

[jmgate]

@kuberry, what version(s) of Python do you support?

[jmgate]

Hopefully the majority of this work will actually take place in TriBITS#307.

[kuberry]

@jmgate For running certain tests in ctests, Python 3.x will work (>=3.4.0).

[kuberry]

I think most everything would work in Python 2.7.x, except for "print variable" vs "print(variable)".

[jmgate]

I think the work in TriBITS#307 is complete, but we'll have to wait for that to be merged and then for TriBITS to be snapshotted into Trilinos. In the meantime, I can start on the script in compadre that will wrap snapshot-dir.py.