Added function to create n-dimensional undefined array.  Thanks StackOverflow!
Made the anti diagonal matrix transformation (originally defined in Level.js) into its own function.
Added test.html and test.'s files to quickly test small JS things - the anti diagonal matrix transform works!
Refactored the lookup for the tile images into its own function, and expanded the lookup to consider tiles which denote ladders (for which the art is included here).
Refactored the img_string_lookup function to be more general and find more than tiles (i.e. blocks) if a flag is set.
Getting closer to something that looks right:  The spacing of the blocks is getting better, but still off.  I think I'm going to have to add padding on both sides so that it lines up correctly.