Sandboxing makes module scripts run inside an isolated lua environments,
making more easier and secure to script
Move and rework TextMessage using the new sandbox system
* Split game module into game and game_interface
* Move core_lib to corelib
* Move miniwindow to corelib
* Introduce init.lua script for initializing the client, giving much more flexibility
* OTClient is no longer Application derived and is much simpler
Eduardo Bart