[gentoo-python] Killing CPython 2.5, 3.1 and PyPy 1.9

[Michał Górny]

Hello, folks.

PyPy 2.1 is out, we expected PyPy3 2.1 and CPython 3.4 at some point.
Then Jython 2.7 (maybe sometime near CPython 3.6).

I think we should start dropping support for really old
implementations. PyPy 1.9 probably has most of the agreement already.

For CPython 2.5, it's mostly virtual/pil giving me creeps. Since old
imaging does not support 3.3 and PIL does not support 2.5, there is no
way all impls could be satisfied with the virtual. So I dropped 2.5
from my PYTHON_TARGETS a while ago and I don't test packages against it
anymore.

For CPython 3.1, I guess nobody really cares about it. At least I don't
recall a single reason to keep it.

What do you think?

(of course, we'd have to ensure updated PYTHON_TARGETS prior to killing)

-- 
Best regards,
Michał Górny