HDF5 data to struct reader

This function loads data from a HDF5 file (or optionally a selected part of it) to a Matlab structure. Nested groups are supported, and included as structs nested inside structs.

It can read all data the low-level HDF5 API can handle. (Matlab's own high-level hdf5* can't read for example chunked datasets, at least as of R2008a.)

Complex numbers are also supported; compound datasets with two fields 'r' and 'i' interpreted as complex numbers.

The function also preserves the order of dimensions in the data read, ie., it permutes the data from C order (that's in the file) to Fortran order (Matlab). This is useful when reading HDF5 files generated by non-Matlab software.