[Python.NET] Retiring Python 2.7

[Benedikt Reinartz]

Hi,

> I think it’s much too early to drop 2.7 - I’m on a mix of 2.7 and 3.6
> at work
> Also, if we’re going to spend some cycles changing the build, let’s
> get 2.4.0 eggs out and get .NET Core properly working? 😎

Just to get this straight, I have no intention of dropping Python 2
support until someone demonstrates that it significantly simplfies the
code and build process. Python 2.7 is currently just one target out of
five, so first priority to me should be to trim down the need of
individual PYTHON3x defines to a single PYTHON3, as this is where
change is happening. Python 2 is a static target.

Of course it would be nice to provide fewer packages, I've outlined my
ideas on this at https://github.com/pythonnet/pythonnet/wiki/Plan, but
I don't see it as an improvement if we just run a -DPYTHON3 over all
code.

Regards
Benedikt