Smarter way of linking VMManager to NavigatedPanel

This decouples NavigatedPanel from the rest of the application session.

(now I just need to get rid of that pesky border!)

[1825]
Remove references to VMManager from NavigatedPanel

[1825]
Clean up. [1825]
Clean copy. [1825]
Improve quality of some image previews.

It appears that things must be within the 0-255 range…

[1825]
Fix for improper cal unit spacing values. [1825]
Remove weirdo import. [1825]

Not sure where that one came from…
Fix needing to click in preview for region change.

[1825]
Show wait cursor while preview grabs data. [1825]
Fix strange usage of Boolean. [1825]
Clean overrides. [1384]
Bring in contents of IDV pull req 35 for testing.

[1384]
Merge remote-tracking branch 'upstream/master' into inq1720_metadata