Preview: open in place

[akaDuality]

When I share designed document via AirPlay iOS suggests to open file in Preview app. But, the app doesn't open file in place.

• [x] Open in place
• [x] QuickLook
• [ ] Thumbnail Won't work. Also tutorial. The same code works fine for macOS
• [x] Thumbnail for macOS
• [ ] Transition from thumbnail to screen
• [x] Any way to close current document
• [x] Also support close from VoiceOver

Refactoring:

• [x] Show document browser as root controller
• [ ] QuickLook: open document during loading, not after presenting
• [ ] Use QuickLook.png for QuickLook on iOS?

Documentation

[akaDuality]

Half of work is done at #62