Update shebangs

If the user installs a custom Bash build, why not use it?

Ref. https://github.com/mathiasbynens/dotfiles/commit/5d1850e041f955c48f5a2241faabddd7af895b58
Improve `note`

Give the Notes.app function the ability to add both `title` and `body`.

Ref. https://github.com/mathiasbynens/dotfiles/commit/b63c7613d0f2619a03f667ae7ff719306462ad23