Remove dead StoreMessage and StoreMessageDisplay

They've been deprecated for a long time, and nothing uses them intentionally.
Bump package as this will break compability.

Also bumps Swat, which isn't strictly necessary, but https://github.com/silverorange/swat/pull/27 fixes a style bug related to this.
Merge pull request #31 from isaacgrant/store-cart-message-cleanup

Store cart message cleanup