* Update install instructions for Bash and Zsh
* Synchronize README.md with `pyenv init`
* Add a ~/.bash_profile note
* Concatenate shims activation into installation for brevity
(Pyenv can't be used meaningfully without shims anyway)
Otherwise, we'd need to duplicate all the ~/.profile shenanigans in both sections
* Update based on feedback
* Proofread
E.g. for a GUI session, ~/.profile is executed by the GUI login "shell" at its startup
so one needs to fully log out and log back in.
Before that, the change would only be seen by shells explicitly started as login shells.
All scripts in libexec/ (excluding pyenv) are called through pyenv,
therefore the shebang lines are not necessary. On some systems this
provides a measurable increase in performance of the shell prompt.
Related to pyenv/pyenv-virtualenv#259