in a good state, RTree is broken so I'm forking to use the one-dimensional Virtualizer class for now.
Replaced the R-Tree with the Virtualizer in most of the appropriate places.
Relatively successfully virtualized list-based rendering w/ the Virtualizer class.
Fully implemented list-based virtualized rendering.
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.
Moves the Virtualizer into the reactive-virtualization project.
Abstracts virtualization into the reactive-virtualization project. Cleans up project quite a bit, speeds up rendering while scrolling.
Committing so I can replace everything with a working version.
Gets rid of DOMElement/DOMNode/Regions in favor of a single unified Values instance. Values is an Observable property container that broadcasts property updates.
Replaces the single-dimension Virtualizer with a Hilbert RTree cache. Adds some basic block-level layouts.