Feature/deprecate py35 and below

[mlshapiro]

Can we do this? Tests are already showing we need to

[jmilloy]

I think we can deprecate python 3.5 even if we can't deprecate python 2. When I asked about this in the fall Matt said we needed to keep python 2 support.

(I had to allow pyproj 2.2 in order to run the setup.py on my machine with python 2. I made that change this morning.)

[coveralls]

Coverage decreased (-0.2%) to 91.677% when pulling ffd53fc on feature/deprecate-py35-and-below into 9076d57 on develop.

[coveralls]

Coverage decreased (-0.2%) to 91.677% when pulling ffd53fc on feature/deprecate-py35-and-below into 9076d57 on develop.

[mlshapiro]

ah ok, so in that case, we can say python >= 3.6, or py 2.7. Too bad we can't deprecate py 2. If thats the case, xarray deprecated python 2 in 0.12, so we'll have to keep it at 0.11.

I'll close this PR and see if I can get the tests to work with setup.py as is

[mpu-creare]

Late to the party, but agree with everything.