thanks for your efforts. This went straight into master.
Most test are working now. Only two path-specific tests are not working (some import errors). But I think we can fix this directly in master.
So what is next? There are for sure some python3 incompatibilities remaining. But it's quite difficult to find them. Some testing would be nice.
I will try to upload a build of the current state of the python3 branch to anaconda, so everybody on linux can test the branch.