Add reprs, a tox.ini, and fix expects version

I've found myself having to add these reprs a couple times to debug things so I'd like to add them to cut down on debug time.

When I tried to run the test suite I got a bunch of errors. It looks like expects is non-backwards compatible at 0.4, so I set a max version of it.

Also adding a `tox.ini` to make it easier/faster to setup the virtualenv and develop locally.