Fixed bug with tank moving into bullet by itself
TankView became even less connected to other entities.
Bullets moved to message-oriented paradigm.
From now clients and game will communicate directly or via RMI. No channels between them anymore.
Now tanks can be spawned.
Two more classes for spawning tanks.
Removed useless add methods and fixed bug with shooting by third tank.
Changed level initialization type.
"Few" refactorings.