refactor: convert error boundary code to Reason

[anmonteiro]

generated code looks like:

// Generated by Melange
'use strict';

const Js__Js_undefined = require("melange.js/js_undefined.bs.js");
const React = require("react");

function errorBoundary(_props) {
  let self = this ;
  React.Component.call(self);
  self.state = {
    error: undefined
  };
}

errorBoundary.prototype = Object.create(React.Component.prototype);

errorBoundary.prototype.componentDidCatch = (function (error, info) {
    let self = this ;
    self.setState({
          error: {
            error: error,
            info: info
          }
        });
  });

errorBoundary.prototype.render = (function () {
    let self = this ;
    if (Js__Js_undefined.testAny(self.state.error)) {
      return self.props.children;
    } else {
      return self.props.fallback(self.state.error);
    }
  });

const make = errorBoundary;

exports.make = make;
/* errorBoundary Not a pure module */