Adding some CommonJS as well as Component support

 * Adds a `component.json` to support [Component](https://github.com/component/component)
 * Adds commonjs exports alongside AMD, using same UMD as d3 itself (also to support CommonJS)
 * Updates `.jshintrc` to allow for node globals (in this case, `module`)
 * Rebuilds the "dist" files (`cal-heatmap[.min].js`)

This should all retain backwards compat :)