Saving and loading acquisition settings

[henrypinkard]

@bls337 In case it is useful for implementing the feature where acquisition settings save alongside the image data. I have written toJSON and fromJSON functions demonstrating how this can be done with the mmcorej.json library. These could be useful templates for implementing something similar.

The Java acquistion engine accepts an optional parameter for adding custom fields to summary metadata, so once it is in the form of mmcorej.json it should be relatively easy to tie in.