add component.json to allow component install

[Component][1] needs a component.json in order to install/build, this PR adds it.

Also added a tiny shim (component.js) so you can simply `require('tv4')` instead of `require('tv4').tv4` from within component.

And I added a component-ized version of the browser tests (`test/index-component.html`).

[1]: https://github.com/component/component