Makes a distinction between a Region's size and its viewport. Adds basic virtualized layout (will need to refactor) inside TextContainer.
Adds an enumerable for the children of an XML element.
Gets rid of unused observables and subscriptions.
Adds the inheritance chain to each element as it's iterated over the first time.
Adds a function to watch a DOMElement for updates and dispatch the next time a "rendered" event is dispatched from the UI.
Adds string constants for the "render" and "rendered" events.
Breaks the Paragraph and Container UI components into separate classes.
Adds the paragraph dom parser/renderer.

Fixes a bug where the rendered children weren't being inserted into the cache in time to measure them before selecting the next item.

Doesn't dispatch as many updates to unchanged DOM elements on scrolling.