The number of unmodified elements to display before and after a chunk of modified elements. This number
determines how blocks are created. If the distance between two changes is less than the double of this value then
those changes are put in the same block (they share the same context).
The object used to split the modified elements into sub-elements in order to produce a more detailed diff. This
allows us to display changes at two levels of granularity (elements and their sub-elements).