add selection mechanism for cloudInfo function object

As mentioned in EP1594 it can be useful to restrict calculation of D32 and other spray properties to a subset of parcels.

• add a predicate selection mechanism similar to vtkCloud etc.

assigned to @mark

Note - code completed but awaiting merge-request !528 (merged) for new reduce methods.

mentioned in commit 5cf52965

mentioned in commit b8c3dc4e

closed

mentioned in commit dd438ffd