Inclusion of Pyenv

[supermensa]

Please add pyenv to the guide, it has greatly simplified managing versions of Python for me.
https://github.com/yyuu/pyenv

[obestwalter]

Also see: #395 pyenv is great :)

[obestwalter]

Also see: https://github.com/kennethreitz/python-guide/pull/402

[obestwalter]

Also see: #728 (I really don't want to be annoying ... I just would like to point out that pyenv is actually state of the art on Unix/Linux and it would be nice if this would be acknowledged in this guide).

[userlerueda]

I think this has been integrated and can be found here. @obestwalter @supermensa do you think that it is enough and that this issue can be closed?

[generalandrew]

@userlerueda I would recommend including it as part of the installation instructions.

For newbies it would make more literal sense to have the installation command for python be pyenv install 2.7.8 for version 2.7.8 instead of brew python and it automagically picking version 2.7. I'd also think that this is more of a future proof when/if homebrew decides brew python => version 3.

[obestwalter]

I'd also think that this is more of a future proof when/if homebrew decides brew python => version 3.

That recently happened, if am not mistaken.