Drop Python 3.3, 3.4, PyPy support; add Python 3.6 support

[brianmay]

No description provided.

[coveralls]

Coverage remained the same at 100.0% when pulling cce48c0 on brianmay:update_python into 5adf32d on TracyWebTech:master.

[seocam]

@brianmay why are we dropping pypy support? We do have people using it in production with pypy.

[brianmay]

Sergio Oliveira <notifications@github.com> writes:

@brianmay why are we dropping pypy support? We do have people using it in production with pypy.

My vague understanding is that the "pypy" target in travis is very old, and often just added by default without good reason. I can put it back if you like, however it looks like we should be using a travis target like "pypy2.7" or "pypy3.5" instead of "pypy". https://docs.travis-ci.com/user/languages/python/#PyPy-Support What versions of pypy do you think we need to support? -- Brian May <brian@linuxpenguins.xyz> https://linuxpenguins.xyz/brian/