Updates docs to include info about folder structure

Fix compile error from change to JavaScriptExecutorFactory constructor

Fixing typo in readme

Make sure the correct bundle is loaded in prod

Make sure the bundle is correctly named

In order for the production bundle to be picked up correctly, make sure it is named *.jsbundle

In prod (or rather when there is no package manger), the fallbackResource is used. And by default that is main.jsbundle. So ensure the thread name is passed along

Fixing typo in example code

Was spending quite some time figuring out why my app was not receiving any messages... ;-)

fixes #1

package has not been tested in a production app, not yet 1.0

turns out react-native link takes the first file that implements
ReactPackage, so RNThreadPackage must come before BaseReactPackage
alphabetically.  Prefixed it with Thread so RNThreadPackage comes first.