[AC-4769] Expose Bundle ID and more to Titanium.App namespace

Currently, the Titanium.App namespace holds various settings regarding to tiapp.xml. However, it does not include the bundle ID of your app (i.e. "com.appcelerator.app", which can be found under the "" tag in tiapp.xml) and possibly more settings. I suggest a generic approach: perhaps a new namespace should be created that uses https://www.npmjs.com/package/xml2js or something similar, to parse the tiapp.xml to an in-app readable JSON-format (lets call the new namespace "Titanium.TiApp"). This would expose anything that the developer might need and it will work for any future additions to tiapp.xml. Then, Titanium.App will only contain values that are not explicitly in tiapp.xml, like: idleTimerDisabled, keyboardVisible, disableNetworkActivityIndicator (see http://docs.appcelerator.com/platform/latest/#!/api/Titanium.App). All other settings that can be found in the "Titanium.TiApp" namespace should then be deprecated in Titanium.App.