Adding a require for pallet to the README.md

This is a question (and a pull request depending on the answer).

In my install I needed to add this line to my initialization files before pallet would actually start editing my Cask file automatically. If I removed the `(require 'pallet)` line and remove/install a package my Cask file would not be edited.

Regardless of the presence of this line, the `pallet-init` and `pallet-update` commands were always available and once I ran one of them, auto updating of the Cask file would start working.

Is there something screwing up my init files at the moment, or is the above behavior correct and a line should be added to the README.md?