Patch contributed by Jim Miller

Using mechanisms developed for ITKv4 to store test and baseline data
on a web resource (Midas or other website).

Data can be referenced using content based hashing scheme.

Still need to configure Extensions to use the Slicer object store.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@20163 3bd1e089-480b-0410-8dfb-8563597acbee