Implement 2 balls, movement with keys, collisions with each other and with walls
small fixes
Small fixes 2
make game work again
move physics properties to entities, using values from config as default
refactor physics calculations
implemented ball collision for varying elasticity and mass
Implement sending input to server, storing history, sending and receiving state (not finished)
Implement working multiplayer with history recomputation, test on localhost
Allow server to run without cocos and pyglet; move state management classes to separate file; add euclid library
Stucture for powerups and entity updating.