Better simulation :)

Change Summary:

Adds brief transition screens between legs of the race
Title bar reflects which leg is being run
Added a "START" and "FINISH" label to a leg's start & end states
Agents that have finished their race are sorted by decreasing score (i.e., the agent that did best on leg i goes first on the ith set of ledges above
Each agent's score is displayed beneath them
Added "Headstart" functionality.
    If a TD agent finishes 10 steps on world 1 before the other two, the TD agent on world 2 starts the simulation    
    on its tenth state.