Add WYSIWYG Matrix constructor about oldimmutablearrays.jl

[twadleigh]

You show here a row-major relationship between arguments of the constructor and the resulting matrix elements. Is this the analogous behavior for Julia arrays? Otherwise, I'd say that a column-major relationship might be more natural, given the memory layout of Julia arrays (and the current layout of the immutable versions).

[jayschwa]

Is this the analogous behavior for Julia arrays?

Kinda sorta:

julia> [11 12 13
        21 22 23]
2x3 Int64 Array:
 11  12  13
 21  22  23

Maybe we can hook into this more native syntax somehow rather than using a constructor. I'll play around with it a bit.

[jayschwa]

Added in 3e893c7:

julia> Matrix3x3([
       11 12 13
       21 22 23
       31 32 33])
3x3 Int64 Matrix3x3:
 11  12  13
 21  22  23
 31  32  33