TODO

Make it work for rotations.
For this, I need to know how to reverse an affine transformation about a 
  different centre. Specifically, if you have an element and apply
  "translate(50px, 50px) rotate(30deg)", it does the translation and rotation
  about its own centre. How do I calculate the matrix that I need to apply to
  the *body* in order to shift and rotate the body so the element appears where
  it should have been before the transformation was applied? I know how to
  invert a matrix, but I don't know how to invert a matrix and take into account
  the different centres of rotation.
UI for rotation: slide-out drawer with rotate icon in it.

Make the resulting document saveable
Pop up a new window with the rendered doc in and ask them to do Save Page As?
POST the content of the page to an online web service and have that download it?
  Note that an online service is no good since the page isn't served from 
  there; the whole point is that it's editable just as a page loaded off 
  the hard drive.
Something else?

Make it not look like arse
Design skills, I have none. I need some. This could be great if it didn't look
  utterly shit.

Think up a name
The only hard things in computer science are cache invalidation and 
  naming things.

Implement image addition
Ask for an image URL, then convert that URL to a data URL (this will need
  some sort of online service) and embed in the page. Note that an online
  service is no good since the page isn't served from there; the whole point
  is that it's editable just as a page loaded off the hard drive. Images
  are done as:
  <h? style="-webkit-transform: translate(150px,105px) scale(0.1); -webkit-transform-origin: 0 0"><img src="data:image/png,%89PNG%0D..."></h?>
  The transform-origin is required, or zooming zooms to the wrong place. Use
  scale to make the image whatever size you want in the overall pres view.

Allow images to be zoomed in and out
Draggable corner?

Implement changing text sizes
An "expander" drawer slides out of highlighted (hovered) items, with six squares
  of increasing size; choosing one changes the nodename

Change display order of items
UI is a challenge. Have lines joining each item to the next item? Show lines
  for this item and the two or three around it, on hover. Should be able to move
  an item to be in another place in the list, as you can if items are just shown
  as a list.
Maybe have a global edit-box button which reorganises everything in a list and
  lets you drag items in the list up and down? Then press the button again to
  go back to different ordering.

Delete all button to delete the instructions

Make big text a lot bigger; small text a lot smaller.

Change background/foreground colours
Slide-out drawer again for foreground colour of text; button in edit box for 
  background colour of presentation. WebKit doesn't have input type=colour?

Make it work in Mozilla
Unlikely, since Moz doesn't have CSS transitions. Is it going to get them?

Think of a logo and make it come up in the corner of the last slide? Intrusive?

Allow editing of notes
Any heading can have a <p> after it which is notes for that heading. These notes
need to be editable through the UI. Another slide-out drawer with an icon, which
when clicked slides out a big drawer with the note in it?

Semanticness
It is Not Very Semantic to have all the content in headers. Talk to someone
like brucel about this.

Presenter view in a different window
  Show slide title, any slides notes, next slide title, timer

Outline mode for creating the thing