dev-python/mox3: add to overlay

Checking on python3 for mox3 as it should be.
dev-python/mox3: drop python3_4

flake8 doesn't support python3_4; thus, we don't
dev-python/hacking: add to overlay
dev-python/mox3: drop discover dependency

Appears to be only useful for python <2.7.  Verified with a run of tests
that it's not required.
dev-python/mox3: add python3_4
dev-python/hacking: use esetup.py to run tests
Use ~ to lock dependencies not =
Drop DISTUTILS_SINGLE_IMPL
Add setuptools dependencies.
dev-python/mox3: use esetup.py for tests
dev-python/flake8: add flake8 to overlay
Merge branch 'master' into dev-python/mox3
dev-python/hacking: drop discover (yet to be verified)
dev-python/hacking: add python3_4 target
dev-python/mox3: drop python3_4
update travis configuration
Merge branch 'master' into dev-python/mox3
dev-python/hacking: drop python3_4
dev-python/hacking: add discover dependence
dev-python/discover: add to overlay