More tests are running under python-3

Include documentation doctests into main test suite. Documentation is
updated to be valid under python-3 and some critical bugs in python-3
are revealed.
Dictionary views are not proxied

Dict views for keys(), items(), and values() are not proxied, making
dicts work in python3 exactly as python2.
Use python3.3 to run documentation tests
Merge branch 'moretests'
Releasing 4.0.0a4