Kyle merge two floorspace files

[kylem038]

This addresses #368 We've added a new icon to the toolbar which will accept a new floorspace json file and merge an incoming floorplan with the current floorplan in state. A few items that should be addressed before merging...

• [x] Naming conventions: As discussed in the issue, we merge stories together in order (The original Story 1 will be merged together with Story 1 from the incoming floorplan) but there can be multiple duplicate namings beyond that. I've implemented something for Spaces where I denote each space as Original or Imported. If that is accepted I can do that same for many of the other properties like windows, doors, etc.
• [x] Update tests based on the decision above
• [x] I haven't touched Projects. After looking closely at trying to merge 2 separate projects it seems that would be unwanted behavior. For example, what if one floorplan has different language set than the other? One wants the grid visible and one doesn't? I'm thinking one should overwrite the other. We could potentially prompt the user before uploading the file to see which one they'd want to keep as the source.

[kylem038]

@bgschiller Thank you for taking the time to review. Did you have any thoughts on the first checkbox in the description? If that sounds good I can update each property to append "Original" and "Imported" to the names to denote what came from where.

[bgschiller]

@kylem038, "Original" and "Imported" work for me. I feel like it might be good to get @DavidGoldwasser 's input on it, if he's available. It's also easy to change later, so you could merge it and let him take a look once it's live.