Reshape() by row or column functionality

[Garic152]

While working on #876, I noticed that the matrix() function from systemds supports a byrow=bool argument which, when used to reshape a matrix, can control whether to reshape it row by row or column by column.

This feature isn't yet included in daphne, so I had to do a little workaround by first transposing the matrix and then using the reshape() function.

A byrow=bool argument like in systemds might be useful in daphne as well, if there are usecases where reshaping column by column is used often.