function createScreePlot(yy)
This function creates the screePlot based on the
results from FPCA() or FPCder()

Input yy : returned object from FPCA().

example:

yy = FPCA(y,t,p);
createScreePlot(yy)
or
p = setDerOptions('nder',0:2);
yy = FPCder(y,t,p);
createScreePlot(yy)