Adding rescale function to simplify common case of scaling image by a factor
Fixing wrapping, kernel scaling issues in resampler
Switching from size_type to long throughout, since the type is used for (signed) offsets
Simplifying wrap check
Caching kernel evaluations (but lookup overhead is large so this will be reverted)
Revert "Caching kernel evaluations (but lookup overhead is large so this will be reverted)"

This reverts commit a7a27675c68cd17cfb38774acf43d8c5e7a9b42b.