Update README.md to include a serial comma to better resolve ambiguity between the three terms HTML, SVG, and CSS. [Wikipedia](http://en.wikipedia.org/wiki/Serial_comma) states that an *omission* of a comma before the last term can suggest a stronger connection between the last two items in a series.
Code that previously assumed a global document or window now uses the related node’s ownerDocument or ownerDocument.defaultView as appropriate. If no related node is available, the corresponding code will crash; however, the rest of D3 will work just fine. For example, you can’t use d3.select(string) unless a global document is available; it just doesn’t make sense. Use d3.select(node) instead, followed by selection.select(string). Code that previously checked for a global on the window (e.g., XDomainRequest) now uses the global context (`this`) rather than the window.