The old version of ExecutionObject (that only takes a device) is still
supported, but you will get a deprecated warning if that is what is
defined.
Supporing this also included sending vtkm::cont::Token through the
vtkm::cont::arg::Transport mechanism, which was a change that propogated
through a lot of code.
This is a subclass of ExecutionObject and a superset of its
functionality. In addition to having a PrepareForExecution method, it
also has a PrepareForControl method that gets an object appropriate for
the control environment. This is helpful for situations where you need
code to work in both environments, such as the functor in an
ArrayHandleTransform.
Also added several runtime checks for execution objects and execution
and cotnrol objects.
