Improve accuracy of vtkWindowedSincPolyDataFilter

Using Hamming windowing function turned out to lead to inaccurate scaling of the output (up to about 1% error, either increase or decrease of the scale).

This commit implements all three window functions that are described in Taubin's paper but leaves the default at Hamming for backward compatibility. It is now recommended to use Blackman window, as it tends to lead to less scaling error.

Note that when passband is set to very small value then shrinkage may occur regardless of the windowing function choice.