Import other `.vodesign` document as frame

[akaDuality]

Documents

• [x] Recognize vodesing files by drag'n'drop
• [x] Insert frames to artboard
  • [x] Copy images
  • [x] Create an unique name for the imported image
  • [x] Offset artboard
• [x] Can add to empty documents
  • [ ] But if document won't open nothing happens
• [x] Image reuse incorrectly
• Zoom level
  • [x] Update zoom lever after addition
  • [ ] Add several images – maximum zoom level not allow to fit images
• [x] Test undo for insertion
• [ ] Add File -> Import to Menu

Images

• [x] Images missing during autosave. As a result had to rewrite all image caches to property wrapper
• [x] Allow to add several images at once
  • [x] And several documents

Bugs

• [ ] Crash had happened when number of document reduced in recent window. Probably I have deleted draft and open recent
• [ ] Frames with the same name couldn't be selected
• [ ] #331
• [ ] App Store Product Card.vodesign contains broken scale for image App Store Product Card.vodesign.zip