Prefer the leading drivers on collisions

When processing driver actions, process first the leading drivers,
preferring those with faster response time. These seems to give better
results when collision happens.
Improve scoring rules for example driver

Previously I assumed that turning is dangerous since you may collide
into other car and loose speed, so switching lane to a lane with a
penguin was scored lower then keeping in the same lane and making no
progress. Now the switching to such lane has higher score and this
driver perform better now.
Rename example driver and improve description

This driver is preferring turns, not jumps.
Remvoe the unused concept of player "life"

We never used the life value of a player, so lets remove it to keep the
game simple as possible.
Starting the race at the bottom of the screen

Starting now at row 6 instead of 4, making the game little more
interesting and more like a real race.
Merge pull request #57 from nirs/game-logic

Game logic