Re-implementing nearest neighbor polar transfrom

Now that some other parts of the code have been ironed out, I thought
I'd try to see if the nearest neighbor transforms would give better
results than they had been.  It seems like oversampling in the radial
and azimuthal direciton by a factor of 2 gives nearly lossless results
(only differences are near edge of image, so unimportant).

Now need to continue expermenting with values/doing median filter in
azimuthal direction as well to find best parameters (really need to get
moving on that...)