Loader for the app. Load all the json files needed (config, translations, map layers...) and add event listeners.
The constructor
Load the complete app
A flag indicating when the layer toolbar must be added
The language in the lng parameter of the url
The mapEditorViewer
The path of the app + TravelNotes ( first part of the json file names )
The url of the TaN file in the fil parameter of the url
The dafault zomm factor
Loading event listeners
Loading the config.json file from the server
Loading map layers
Loading translations
Loading TravelNotes
Read the url. Search a 'fil' parameter, a 'lng' parameter and a 'lay' in the url.