Support for column-major layout in binary format?

[johnstairs]

The C++ types for multi-dimensional arrays (yardl::FixedNDArray, yardl::NDArray, and yardl::DynamicNDArray) are all locked to row-major layout at compile-time.

We will eventually support languages that default to column-major ordering. HDF5 requires data to be written in row-major order, so we will need to convert. For the binary format, we could do the same, or we could prefix each array with a byte indicating the layout. This could avoid expensive permutations if readers and writers are both working with column-major ordering.

[johnstairs]

We will address this in #78