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 merge request is Phase 1 of several to implement the distributed parallel
contour tree in VTKm. This merge requests adds the base outline for the
algorithm. The implementation of the details of the algorithm in the
BoundaryRestrictedAugmentedContourTree.h is currently still missing.
However, these will require a substantial (~3000) lines of additional code.
The goal is to stage the integration process across merge requests to make
the review process simpler.
