This mechanism sets up CMake variables that allow a user to select which
modules/libraries to create. Dependencies will be tracked down to ensure
that all of a module's dependencies are also enabled.
The modules are also arranged into groups.
Groups allow you to set the enable flag for a group of modules at once.
Thus, if you have several modules that are likely to be used together,
you can create a group for them.
This can be handy in converting user-friendly CMake options (such as
`VTKm_ENABLE_RENDERING`) to the modules that enable that by pointing to
the appropriate group.
This commit address issue #713 and removes the need to pass information
about the spatial decomposition (block origins, block sizes, block index
and blocks per dimension) to the contour tree filter. Block origin
information is added to CellSetStructured (as GlobalPointSize) and the
distributed contour tree filter will get this information from
CellSetStructured instead of expecting it as parameters to the
constructor. Information about blocks per dimension and block indices
are computed from the information in CellSetStructure albeit requiring
global communication across all ranks. To avoid this communication cost,
the caller of the filter may explicitly specify this information via the
SetBlockIndices() method.
The `DynamicCellSet` (and the related `DynamicCellSetBase`) are
deprecated and replaced with `UnknownCellSet` (and `UncertainCellSet`).
Thus, `UnknownCellSet` has some methods inherited from `DynamicCellSet`
but replaced with other functionality. These methods are now marked as
deprecated and their use is removed.
It used to be the case where you needed to call `ResetTypes` on a
`VariantArrayHandle` before using `ArrayCopy` to limit the types it gets
compiled for. However, there is now a general form for
`UnknownArrayHandle`, so `ResetTypes` no longer does anything useful in
this case. Remove the use of that.
