remove remark about the "logical address" idea for formats. Caused needless confusion, and seems unlikely to be sound in general
put the orientation in the Rectilinear layout type classs and start putting some documentation on the methods
not exporting the various (M)Vector constructors for unboxed vectors of (Shape n a) values, because that forces haddock to list ALL the Unboxed Vector instances known to humantity (or at least numerical) to be listed in the haddocks!   My Myopic (or not?) work around for now is to provide a  "morphism" between a sized lists of Vectors and Vectors of sized lists!

NB: the simpler solution would just be to put the relevant definitions in a Shape.Internal / Shape.Base module. And perhaps I should look into that later