Multidimensional arrays for D

[Marco Leise]

This looks nice. I like how much is possible with the foreach delegates.  
For the most part when I need a matrix, it is for 2D rotation and  
translation or OpenGL. It would be nice if one day OpenGL bindings would  
have overloads that accept your matrices. The row/coumn order is different  
there and I bet most realtime gfx fanatics would want optimized versions  
for the common 4x4 or 3x3 matrix types. Close to handwritten assembler so  
to say. But even without top-notch performance some nice demo code could  
show up.