Fixes loading modules from transpiled es6.

In many es6 transpilers, `export default Component` creates the syntax
`module.export = { default: Component }`. This adds a check so that if a
`require`d component contains a `default` property, it is used.
Merge pull request #10 from ajacksified/fix-for-transpiled-es6-module-loading

Fixes loading modules from transpiled es6.