Upgrade to rustc 0.13.0-dev (c8d6e3b2c 2014-11-18 19:11:43 +0000)
Implements zero-copy html parsing.

Instead of using strings, html5ever now uses Iobufs and Spans over
Iobufs to represent the raw html data. This allows us to do all of
the parsing without copying the HTML into a tree of strings: it can
be Spans and Iobufs all the way down.