Fix ugoira to work with notes.

* Change the id of the canvas tag to 'image'. This is what the notes JS
  expects. It's also what the shift+e edit shortcut depends on.
* Add data-original-width/height attributes, which are what the notes JS
  needs to position notes properly.
* Add all the other data attributes that regular images have, because
  why not.
Merge pull request #2272 from evazion/ugoira-notes

Fix ugoira to work with notes.