mv evolveddiskdf up, bc it's typically the slowest
only submit coverage info for python 2.7
we'll just assume that if 3.4 works, 3.3 does also, don't always test 3.3
add pragmas for Py3
rm unnecessary getinitstate from Orbit, because it's useless for new-style class
fix nemo_accpars test w/ Potential function, but just a single instance
cleanup .travis.yml somewhat