Sqlalchemy branch upgraded to support Python 3, and got all tests working

The sql code hadn't been written for Python 3 compatibility.  This pull request fixes that.  Also, when I tried to run the tests (python setup.py test), I encountered several problems which I also fixed so that now all of the tests pass on Python 3.4 (without redis installed).

With your approval, I would next plan to merge the develop branch into the sqlalchemy branch and offer another pull request.  (Still new to git and github, have been using mercurial which has a very different notion of what a "branch" is, so I get confused with git branches).