Drop support for Python 3.3

[jaraco]

The tests on failing on Python 3.3 due to pytest-dev/pytest#2966, blocking releases.

[jaraco]

I've force-built this job to cut the release of 12.0.2.

[webknjaz]

I'm sure it's safe to just drop 3.3

[jaraco]

Good point. Rather than waiting for upstream pytest to fix their distribution, let's just drop support.

[webknjaz]

There's nothing to fix in pytest upstream: they've officially dropped support for 2.6 and 3.3 in their latest release. We can only pin version of this dependency.

[jaraco]

There is an upstream bug - the 3.3 release doesn't effectively declare dropped support for 3.3 but its dependency (py) does... so pip attempts to install it and then fails.

[webknjaz]

Oh, I see. But it doesn't change the fact that 3.3 isn't supported anymore :)