Matrices stored in row-major order

[nic-barbara]

All the matrices in the Model and Data objects are currently stored in row-major form in stead of column-major like other arrays in Julia. This means that the elements are not in the correct order, which will cause confusion and make usability much less neat. Can we find a nice way around this?

[nic-barbara]

For now, users can do something like

row2col(M::AbstractMatrix) = transpose(reshape(M, size(M, 2), size(M, 1)))

when they need to access any matrices in the model or data structs, but we should have a better solution.