Added iamgeDetails as a JSON state object
Added JSON State object to hold state which doesn't get submitted but is
necessary to update the form on changes.
Table now uses async update properly so state is preserved until the
page is left or refreshed.
Table now updates correctly when switching between tag mappings.
Changed the behaviour of mapping change to set checkboxes checked if the
image has a matching token or it is serverselected. Otherwise not
checked.