Rename $HOME/.bin to $HOME/bin.

I generally only hide dotfiles or things that are related to
dotfiles.
Use gh instead of Hub.

[gh](https://github.com/jingweno/gh) is on track to becoming the
official GitHub CLI, so let's favor that. It's also fast as hell.
Remove Homebrew PATH munging.

My dotfiles take care of this already.
Don't add $HOME/.rbenv/bin to $PATH.

My dotfiles use `rbenv init -`, which does it for us.
I don't need rcm.
Render the installation files.