Remove custom git executables

They can now be found in the `git` role in [jcf/dotfiles][].

[jcf/dotfiles]: https://github.com/jcf/dotfiles.
Remove Heroku executables

Relocated to the `heroku` role in [jcf/dotfiles][].

[jcf/dotfiles]: https://github.com/jcf/dotfiles
Remove Emacs executables

Relocated to the `emacs` role in [jcf/dotfiles][].

[jcf/dotfiles]: https://github.com/jcf/dotfiles
Remove `relx`

Relocated to the `erlang` role in [jcf/dotfiles][].

[jcf/dotfiles]: https://github.com/jcf/dotfiles
Remove `gctags`

Relocated to the `emacs` role in [jcf/dotfiles][].

[jcf/dotfiles]: https://github.com/jcf/dotfiles
Remove `lb`
Move remaining executables into dotfiles
Replace bin with ~/.bin