Experimental Version Update

Changelog 2.0-0a13d1bb3 (partly compatible with productive version) *New: Weekly-Challenges appear in the ingame and online highscores *Improvement: Time-Mode stations show icons of what wagon will appear when solving the task *Change: Time-Mode now features an increasing mining-speed linearly increasing with the played time *Bug fix: Possible cross-play errors when connecting to lobbies of the productive version