.travis.yml: Only install `prospector` on non-Python 3.5 platforms. It appears not to Python 3.5 compatible.
.travis.yml: Only install `prospector` on non-Python 3.5 platforms. It appears not to Python 3.5 compatible.

paulgb/runipy,nanshe-org/runipy,jakirkham/runipy,DudLab/runipy