Attempted Changes Suggested By Prof. Clark

changed propagation to correct method as defined by slides.  angle does
not appear to work correctly, always moving too fast.  Also attempted to
fix weighting, but I don't think that I understood Prof. Clarks
directions.

Also, I made it so that it will always place random particles, because
just because we have a high weighting of certain particles doesn't mean
that those particles are necessarily correct.