Version 2.4.4 released

The new version provides a tool for symmetric fluid dynamic registration, some local-cmeans based segmentation tool, new image filters, and it adds compatibility for VTK-7 data IO.

The new version can also be run from a docker image.

In addition the new version fixes a number of issues:

• [tickets:#129]: Move all optional parts to addons,
• [tickets:#167]: Add an alternative FastICA that is independend of IT++,
• [tickets:#191]: Use C11 integer data types to ensure constistent data sizes,
• [tickets:#192]: Replace lazy copying wit move semantics,
• [tickets:#193]: Make documentation tool and nipype interfaces compatible with Python 3,
• [tickets:#194]: Create a complete facate for XML handling and remove dependency from libxml++, and
• [tickets:#195]: Correct errors in Nifti s-form handling.