Build from CommonJS source.

- Uses r.js RequireJS optimizer to build release/q.amd.js.
- Creates a temp file with `window.Q = require("./q");` and browserifies that to produce release/q.js.
- Minifies both to produce release/q.min.js and release/q.amd.min.js.
- Browser spec runner uses release/q.js.
Use grunt-global-wrap and grunt-amd-wrap.

Notably, this gains us:

- An AMD version of queue.js.
- The AMD version of q.js is no longer using a named declaration.
- The AMD version no longer strips our `"use strict"`.
- The AMD version is shorter.
- The global version is no longer using that somewhat-unfortunate hack, instead encapsulating it behind a declarative config.

Also added grunt-contrib-clean.
Use grunt-s3 to upload builds via Travis.