add support for react components in circle displayText

[turbio]

This is completely compatible with the existing behavior. The only difference is when the displayText of a circle is an object, it will use react to mount that object. Otherwise it will behave as before and set the circles text to displayText or d._id.

[kauffecup]

also would you be able to update the readme and provide an example (perhaps even w/ a screenshot)?

once you do these two things i'll up the version number and re-publish it to npm

[kauffecup]

let's instead add a different property (instead of mooching off of displayText). maybe something like innerComponent or just component. that'd each this if statement to something like:

if (!!d.innerComponent) {
  ReactDOM.render(d.innerComponent);
} else {
  ...
}