Final work
*On/off setting implementation for navigation bar (navbar_enabled)
* Authentication status check
* Javascript error handling if navigation bar container is not rendered (the script will not be loaded in that case)
* Creation of README.txt file
* Implementation of help texts (description) in configuration
* Some code improvements, cleanup, generalization, defining constants, comments etc...
* Incrementing version number
* All multilingual literals moved to standard lang file + implementation of passing languages to js file
* Implementation of skip navbar functionality