Add skeleton for suite testing run-length encoded arrays
Add tests for the run-length algebra

Test all of the methods to see if they give the expected result on
a simple test matrix.
Add unit tests for top surface creation of a sample grid
Allow X and Y to work in 3D too

If we specify dimensions in the plane, they can work as dimensions in
space as well.
Add missing enumeration of all 3D sides
Add comparison operator for carriers
Support streaming 3D side objects to output
Add comment about the orientation of the sides
Make sure that we have Cartesian indices for grid

If the grid is completely structured with no deformed or missing
cells, then the grid creation routines won't supply any logical
indices! We create them ourselves in that case, to avoid yet another
branch in the code below.
Add unit test for Cartesian index calculations
Merge pull request #35 from rolk/035_test

Unit tests for central algebras