ensight case with multiple clouds

ensight only supports a single set of measured values. Outputting multiple clouds for a case is an error.

Could remedy by only emitting the first cloud and either ignore any others or creating separate case files for each of them.

The only problem with this approach is that we still need a model: entry in the case. The mesh bounding box would be a reasonable thing to generate.

@graups

mentioned in issue #902

changed milestone to %v1812

From looking through the CEI/ANSYS support site, it looks like their preference currently is to merge everything into a single cloud of measured values and add something like a "cloud_set" scalar variable to the measured data so that you can still isolate and interrogate specific clouds if needed based on the "cloud_set" scalar.

• another cross-reference to the same noted issue: 036c3b72