By removing the ability to have multiple CellSets in a DataSet
we can simplify the following things:
- Cell Fields now don't require a CellSet name when being constructed
- Filters don't need to manage what the active cellset is
Now that the dispatcher does its own TryExecute, filters do not need to
do that. This change requires all worklets called by filters to be able
to execute without knowing the device a priori.
The added files provide support for Lagrangian analysis of velocity fields of time-varying data. Examples show how to use the filter to generate data and a second example demonstrates consuming generated information to calculate new particle trajectories.
