Load players from the .xml file

Players already known by the system are loaded.
TODO:
* save the newly added players. Sadly, unlike a regular client app, it seems there is no way to modify the players.xml file.
Relove useless cache manifest

As the app will be downloaded as a zip, or a website will host all the files, a webapp that is accessed online and then used offline isn't a scenario to consider.
title update