Rename PIL.version to PIL._version and remove it from module

[homm]

Partially fixes #3082.

It is really confusing for people to find three different constants in PIL module: VERSION, PILLOW_VERSION, __version__ and version. While VERSION is here for historical reasons and does matter, version is module is not required to end user at all. My suggestion is to hide it from users by removing from namespace:

In [1]: from PIL import _version
ImportError: cannot import name _version  # Python 2 only

In [2]: import PIL

In [3]: PIL._version
AttributeError: 'module' object has no attribute '_version'

[hugovk]

I get a slightly different result for the first import:

Python 3.6.4 (default, Mar  1 2018, 18:36:50)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from PIL import _version

>>> _version.__version__
'5.2.0.dev0'

>>> import PIL

>>> PIL._version
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'PIL' has no attribute '_version'

[homm]

Hmm, looks like python 2 vs 3 difference. Anyway, from PIL import _version is the direct call for people who know what they are doing, while PIL.version could be suggested by the code completion.

[aclark4life]

@wiredfool will be the one to convince here, probably. I definitely don't care … assuming we are moving from "really confusing" to "less or confusing" or even better "no confusion anymore".

[wiredfool]

Whatever.

Don't break the single version in c & python, and don't break the world by removing the PIL 1.1.7 version until we do a major release.

[homm]

Don't break the single version in c & python,

Check

don't break the world by removing the PIL 1.1.7 version until we do a major release

Check