Launcher could try to update the game if the update contains a new file

[Kromster80]

Launcher refuses to update the game if the update contains a new file, which the local client already has. So, if I create a new map, and send that map to several players for early testing, and then the map is released in the game, every single one of us has to either delete the map from the game before updating it, or download the entire game.

We could check if that's a new map situation (added files) and ask a player if he wants to overwrite those.
Obviously this wont work for changed files.