The bare minimum to get selector working with both python 2 and 3

I've been unable to suss out how the tests are supposed to work
so my changes have not been validated against the tests. _However_
I've been using this code in my own testing of getting TiddlyWeb
working with python 2 and 3 and it is working great there.

change version info

remove wsgiref requirement

read version from file as text not bytes
Merge pull request #20 from cdent/py2and3

The bare minimum to get selector working with both python 2 and 3