First draft seam-carving (vertical only, slow...)
Added vertical...revealed problems apply block-parallel transfer to this problem.
Seam carving is mostly working!  Still problems with very large contractions.
Adding unit tests, tracking down niggly issues.
Reasonable carver...not fully parallel yet.
A bit of cleanup.
Fixed lingering type issues with seam carving.
Updated documentation.
Merge branch 'seam-carving' of github.com:JosephCottam/AbstractRendering into seam-carving
WIP: All but inner-transfer items migrated to specialized-with-process.
WIP: Progress...but not complete.
WIP: More progress on the forked-specialize.
Tests passing with new combinators.
Added 'start' factory.
Removed references to chain in presets
Chain removed from ARServer.
WIP: Removing chain...need to deal with CoC issues....
No more RLE, but everything type checks.
Chain fully removed....errors in contours.
Removed easy references to the default renderer....now for the hard ones.