Attempt to address Issue-191.

[markpbaggett]

What Does this Do

This attempts to address Issue-191. That issue describes a problem where homepage props are dropped from Manifests in a Collection if the manifest was created via the make_ manifest() helper. Oddly, the issue doesn't exist if manifests are created and added to the Collection in other ways.

The issue appears to be that the helper uses the Manifest class rather than ManifestRef. If we switch the classes, things seem to work as expected.

Todo: what if items prop exists in incoming kwargs?

Any potential regressions

I don't think so. I've added ManifestRef to the AutoIdConfig helper incase someone was using make_manifest() without adding an id property since that worked on Manifest but not ManifestRef. I've also had to add ManifestRef to the AutoLang helper. For some reason, this doesn't work on ManifestRef even though Reference is listed.

[glenrobson]

I don't think Manifests can be embedded in Collections so I think this change is correct. I'm not sure why it was breaking homepage though.