Release with nodejs, expressjs and handlebars

This release makes a paradigm shift in the files serving, as it moves the server side code from php to nodejs and expressjs. Therefore the file changes between this release and the previous one, on December 2017, are substantial.

The loading time now is also much faster, since when the node script starts to run, all the languages and countries informations are kept in memory in a JS object, for faster delivery. With the previous approach the script had to read the correspondent file with the country information.

The directories names were also changed to fulfil the node directories structure, and thus the building scripts are kept in the build/ directory whilst the ready to use code are kept in the bin/ directory.