Ability polish

- Pull the TestClass ability/effect library up a level. That file can
contain both abilities and effects. It has a boilerplate header that
will become Canonical.
- Add the Util.Ability library with its first helper.
- Actually give Shoop da Whoop its onBattleSetup installer. And some
descriptions.
- Hey, we really need to decide on a markup for descriptions.
- Fix some typos.