Marked the old versions of PrepareFor* that do not use tokens as
deprecated and moved all of the code to use the new versions that
require a token. This makes the scope of the execution object more
explicit so that it will be kept while in use and can potentially be
reclaimed afterward.
The Invoker is a control side object that handles the construction
of the relevant worklet dispatcher. Moving it to control makes it
obvious that it isn't an algorithm itself but a way to launch
worklets.
These changes caused some warnings in clang to show up based on virtual
methods in other cell locators. Hence, the rest of the cell locators
have also had some of their code moved to vtkm_cont.
All of the methods in CellLocatorBoundingIntervalHierarchy were listed in
header files. This is sometimes problematic with virtual methods. Since
everything implemented in it can just be embedded in a library, move the
code into the vtkm_cont library.
