Allow pages to be edited without being entirely rewritten

[MattHeard]

A lot of users make typos but don't notice them until after they submit their pages. They are currently unable to make any further changes to the pages after they have been submitted, so they have these glaring typos mock them forever, like stains permanently rubbed into the tapestry of their story, ruining their dream of writing the story as perfectly as they imagine it.

There are some important questions:

1. What is the difference between editing a page and rewriting a page? A rewritten page might have no resemblance to the original version at all, while an edited page has the same content, with minor changes.
2. What is a minor change? Maybe if more than 5% of the text of a page is modified, it could no longer be considered minor. This is a coarse way of dealing with the question because minor/major changes have more to do with how they affect the story than about how much text is changed.
3. What happens to the original version after a page is edited? Currently, rewrites create alternatives with their own trees. Doing this for a small typo would be overkill, as it would effectively truncate the tree from the edited tree (making it weigh less, too, in the version random selection algorithm).

[MattHeard]

I think that the best solution is the most difficult solution: redefine stories from being trees to being general directed graphs, and allows all edits and rewrites to copy the edges to the existing children vertices of the original page. Then, give tools to the users to prune and connect edges where they see fit.