Wrap for python std::vector<ImagePointer> in helper functions.

[phcerdan]

Asked in the discourse forum: https://discourse.itk.org/t/how-to-wrap-a-std-vector-imagepointer-in-swig-with-itkwrap/227

[phcerdan]

WIP in branch: https://github.com/InsightSoftwareConsortium/ITKIsotropicWavelets/tree/use_vector_container

This wip was using itkVectorContainer instead of std::vector. I think it would be better the std::vector option.

[phcerdan]

@fbudin69500 merged in ITK an std::vector wrapping: InsightSoftwareConsortium/ITK@bd8169b

We just need to figure out how to re-use the wrapping in an external module.

[dzenanz]

Can this issue be closed now?

[phcerdan]

I don't think anything has changed to close it. Are open issues a burden? We can add a enhancement label to it, to differentiate them from bugs.

[dzenanz]

CI with Python packages built successfully, that's why I thought we could close a couple of these bugs.