TODO: Test fails because of problems with setting up multiple instances
of xout in the same process

TFixedImage as the ImageSource template since the output image is
always resampled to the fixed image domain.

TODO: Fix 'error while setting up xout' error when running multiple
ElastixFilters in the same binary (see ELASTIX-56 in SuperElastix Jira)

Adds a stand-alone ITK filter that wraps the elastix library
in a fully pipeline-compatible process object. The original
library interface was deprecated in favor of direct use of
elastix internals in the filter's GenerateData() for more
control over pipeline inputs and outputs.

TODO: Support multiple fixed and moving images
TODO: Return TransformParameters

WIP: Segmentation fault when trying to access result image

This build fails because VectorContainer has a private default
constructor