Move tokenizer tests to nose

--HG--
extra : rebase_source : 690f67ebe16128990d5a788d1c53833c1f0af2f4
Clean up a function name that confuses nose
Add "poster" as an acceptable attribute of <video>

This commit adds support for the "poster" attribute, marking its value
as being a URI.
Add support for <video preload=...>, <audio preload=...>

This commit adds "preload" to the set of acceptable attributes on video
and audio elements.
Welcome to Python 3.

We now fail the same three tests on both Py2 and Py3. I'm fairly certain the
meta-preparser among other things is broken on Py3, but we have no tests for
it. (We should fix that.)
Merge.
Fix automerge issues
Remove debug omission of stdout from tokenzier tests.
First hack at splitting InputStream up into a binary and Unicode class pair.
Regenerate the Py2 code using awkwardduet 1.1a4.

This finally sorts out the unicode/str mess, so yay!
Re-run 3to2, and fix where something had gone uncommitted in Python3 before.
Remove a lot of old 2.3/2.4 support code
Move the python3 to master, giving a single, unified codebase.

This works on Python 2 (2.6 and above) and 3 (all releases). It also
provides a minor improvement in performance on Python 2 compared
with the old master, due to lack of implicit str/unicode
conversions.