Reorganize core JS files

Reviewed By: lexs

Differential Revision: D3987463

fbshipit-source-id: fa8f1d1bea7ed699120b9705ddc1c83767fcf8e4

lib/InitializeJavaScriptAppEngine.js

@@ -12,4 +12,4 @@
 
 // This is a forwarding module to allow React to require React Native internals
 // as node dependency
-module.exports = require('InitializeJavaScriptAppEngine');
+module.exports = require('InitializeCore');