Update docs and support empty PropTypes

[coopy]

1. Update the source prop docs to say source={docgen.parse(require("!!raw!../src/components/ur-awsum-component"))
2. Add support for empty PropTypes

[boygirl]

I think empty empty PropTypes is already supported in that you can leave off the source prop, and the prop table wont be rendered.

[coopy]

With the existing boilerplate component (with an undefined Component.propTypes), Ecology bombs: api.js:24 Uncaught TypeError: Cannot convert undefined or null to object