Trend and detrend: Moving Average Operator

Dear All,

It would be great if the Moving Average Operator could include a "trend" and the "variance after removing the trend".
As far as I'm aware it will take no more than 20 lines of code to add these.
I have code for computing these features on a double[] for a given window size in Java.
So I'm willing to help adding this functionality.

Best regards,

Wessel