I should be able to edit a Property, much the same way as I create it

(User Story, Closed -> Fixed, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor, Properties
Summary: This actually borders on a usability bug. Creating a Property is fairly easy, but modifying one is irritatingly hard. Once we are displaying the appropriate meta-Properties for a given Property based on its Type, the existing workflow (Actions -> All Properties -> the right Property -> Edit -> figure out the meta-Property -> add it) becomes utterly idiotic. Instead, I should be able to edit the Property straightforwardly.
Details TBD, but it makes most sense that I should be able to click on a Property's name (or some such) in the Thing Editor, to kick into the Property Editor. The Property Editor should be, insofar as possible, identical to the Property Creation panel.
If a meta-Property can't be changed, that should be indicated somehow. For example, if we don't let you change the Collection (which we currently don't), grey that out.
All of this probably implies refactoring the Property Creation panel. But it likely needs rewriting for the Model Designer page anyway.