Map conflict between client and server

[Cellule]

It is possible to have an incoherence between the clients and the server.
This happens if 2 maps have the same name.

OnlineLobbyControl.CallbackMapListForMapDownload(...)
tries to find the map from its name rather than the id. Needs refactoring

[Cellule]

Uses map name and author name to find the right maps, still not good enough, but better