ENH: Allow SpatialObject Readers/Writers to use new MetaIO format

[aylward]

Updates to MetaIO allow for the specification of the file format to write and how to interpret files that are read. Two versions are supported:

• Version 0 [default]: is not able to completely/accurately represent a spatialobject scene containing images. For images, the image transform and its parent-object transfer were mixed / mishandled.
• Version 1: fixes the errors of version 0, but it introduces additional tag-value pairs (e.g., ElementDirection) that will throw warnings if read by previous MetaIO code/applications.

If you are using SpatialObjects, we strongly recommend specifying SetMetaIOVersion(1) for the SpatialObject Readers and Writers before calling Update().

This commit is dependent on PR https://github.com/InsightSoftwareConsortium/ITK/pull/4739 and PR https://github.com/InsightSoftwareConsortium/ITK/pull/4742

[aylward]

Note that this PR is dependent on the merge of two PRs.

Specifically, it is dependent on https://github.com/InsightSoftwareConsortium/ITK/pull/4742 which is dependent on PR https://github.com/InsightSoftwareConsortium/ITK/pull/4739