Additional smoothing algorithm

[Philipp K. J. <ja...@ie...>]

I have developed some code for a new smoothing
algorithm, which adds some functionality to gnuplot
which I have long been desperate for: a way to plot
cumulative distribution functions directly from data.

The new algorithm is similar to (and built on top of)
"smooth frequency". Like "smooth frequency", it 
sorts data points in ascending order of x-values, but
then replaces each y-value with the cumulative sum 
of all y-values to the left of the current data point. 
 
I have submitted the code as patch 1962130.

Please take a look and tell me what you think. The 
changes are small and very well localized.

Best,

		Ph.