Map: remove using 'this.' when not necessary
Map: build is made public
Map: Added toString() method

Used to transfer map scheme via network
Map: number of empty cells is counted
Map: findTileByType() refactored

such that it is now possible to get tile of any type, not just Helper
Created Listener for receiving commands from Server
Created Sender for sending data to Server
Controller: declare constants marking self/enemy
Shot: shooter can be determined
Angle of enemy tank can be updated in view
Server/Client integration

Client is buggy, cannot commit file partially