This method had a problem when calling from another script.
Updated Sauvola to be independent of the the calling location.
Added structure.Base to contain system-wide configuration variables.
Removed a print call originally used for debugging
Changed global NAME and DESC variables to allow printing of operations
that are not named.
Updated referencing in the example
Added the Method Class as a subclass of list

This class can be used to store an operation stack to perform on an
image. The list of operations can be increased indefinitely. The
applyTo() function can be used to apply the stack to a given image.
Removed unused imports