Use packages clause in setup.py instead of py_modules
Use packages clause in setup.py instead of py_modules

Otherwise setup looks for ev3dev.py, does not find it and installs
nothing. Forgot to copy this from @EricPobot's changes.

dwalton76/ev3dev-lang-python,rhempel/ev3dev-lang-python,dwalton76/ev3dev-lang-python,ensonic/ev3dev-lang-python,ddemidov/ev3dev-lang-python-1,ensonic/ev3dev-lang-python-1