Port of Karsten Schmidts GrayScott implementation into CoffeeScript
##API
###Constructor
grayscott = new GrayScott(width, height)
grayscott.setCoefficients(Du, Dv, F, k)
Sets diffuse U , diffuse V, and the coefficient F and k
The defaults are 0.023, 0.077, 0.16, 0.08
grayscott.reset()
Reset the matrix to initial state
grayscott.update()
Updates the simulation for one time frame
grayScott.v
Float64Array holding the values of the simulation