Bugfixes on client/server comm

I fixed some of the stuff. The assigning citizens should work now. saving and retrieving
And there were some timing issues, where for example the city was loaded and tried to place the buildings but their models werent loaded yet
or the GUI tried to update the idle citizens but it didnt know about the total amount of citizens in the city yet
Now the game wont start until you've established a connection to the server and received your 'city'