Add "CellProfiler can run on a cluster!"

[dlogan]

Well, not that text exactly, but we should advertise better that CP can run on a cluster/headless.

The genesis for this was a grant discussion in which we thought the reviewers might not have understood that CP can be parallelized.

[bledford87]

@bethac07 How do you feel about my adding this as a note to this page: https://cellprofiler.org/getting-started

If so, do you have suggestions for the language?

[bethac07]

In general, I'd say we want to point people at our cluster documentation on the CellProfiler github, and the video tutorial, but since we're still updating the former, I'd say let's put a pin in this for a couple weeks.