Class Orbit implements Runnable - Applet, handles user interaction
	public methods
		start
		stop
		suspend
		run
		paint

Class Particle - Object, essentially massless particle
	instance properties
		double x, y, vx, vy
		int color
	private methods

Class N2FCsimulator - Object implements Runnable, singleton, simulation system
	properties
		particles - ArrayList of Particle[]
	public methods
		start
		stop
		run
		integrate
			arguments:
				double[] {v0, theta0}
				double timestep
				int iterations
				double scale
			returns
				ArrayList of ArrayList of double[] (orbit path)
	private methods
		integrator
			arguments:
				double[] {rx, ry, vx, vy}
				double timestep
			returns
				double[] {rx, ry, vx, vy} 
		macc
		acc

http://download.oracle.com/javase/1.4.2/docs/api/java/awt/event/InputEvent.html
http://download.oracle.com/javase/6/docs/api/java/util/Collections.html
http://www.learn-java-tutorial.com/Java-Collections.cfm
http://download.oracle.com/javase/tutorial/jdbc/basics/examples/OutputApplet.java
http://profs.etsmtl.ca/mmcguffin/learn/java/04-mouseInput/
file:///Users/dakotablair/Documents/TenSen/research/orbit/trunk/java/Orbit.html


A user story
	The user enters the initial conditions.
	The user clicks plot.
	The user particle and two perturbed particles are created.
	Their paths are simulated in a thread.
	The simulator notifies the applet after the user particle
		has moved farther than a pixel from the last paint.
	The applet paints the path, using clipping and double-buffering.
	The simulator stops at the user-specified iteration.

	public methods
		simulate
			arguments:
				double timestep
				int iterations
			returns
				ArrayList orbit path