Added a RNG Interface to be used for our RNG and a RNG using Java's Random class
Moved loop of PedestrianSimulation into a new SimulationThread object

This change was made to allow the use of multiple threads.  The
visualization will run in the Animation Thread, while the simulation
will run in another thread.
Added markers for People
Changed visibility of some variables, moved several methods to the SimulationTimer object
Changed the color used for the Model Building
Corrected small indexing error