Move testdata submodule to using HTTPS.

This provides read/write access to those of us with write access
without forcing everyone to authenticate to read it.
add rudimentary Sphinx documentation
minor documentation fixes
convert requirements-*.txt to be inclusive; flake8 script introduced
always include flake8 in tests
mock C extensions in doc/conf.py for readthedocs.org
Fix #51: DataLossWarning hiding real exceptions in parser.

Previously we stopped parser tests once DataLossWarning was raised; we
now run let the parser run to completion before checking for raised
warnings. This hid several cases of where real exceptions were raised
after DataLossWarning was raised. This commit reveals these real
exceptions in the testsuite and fixes current failure.

Similar fixes are needed for the other tests.
Add release date for 1.0b1.
Move default_etree to utils.py and use it for the treewalker too.
Add pypy to tox by default.

It's quite probable fewer people will have PyPy installed, but I
doubt many will have four versions of CPython installed either.
Fix release version.
Clarify variable names in test_parser.py.
Bump version to 1.0b2.
Fix the two cases of us using old-style classes on Python 2.
Don't needlessly scramble attribute order while walking an etree
Merge pull request #55 from ambv/master

Use OrderedDict for arguments in etree walker
Merge branch 'master' into dom2sax

Conflicts:
	html5lib/treebuilders/__init__.py
Add __all__ to utils.py to explicitly export default_etree import

This silences flake.