Make Fantasy Land compatible

Hi @raganwald,

Coming away from the Promises/A+ debate, I started to work on a JavaScript specification for interoperability of common algebraic structures. It's aptly called [Fantasy Land](https://github.com/pufuwozu/fantasy-land).

I noticed supervis.es has definitions of structures which have semigroups and monads - the only change to make it "Fantasy Land compatible" is to change some names. No pressure to include this, I can understand you finding the names useful. Common names will just let users abstract over those structures (see [here](https://github.com/pufuwozu/fantasy-sorcery/blob/master/index.js) for an example).

The Fantasy Land specification also includes laws. I'm not sure if this library satisfies them but I think it's worth nominally satisfying the specification.

Thanks!