hdf5doc

Purpose:
    Added new section for High-level HDF5 APIS.
    Added links to HDF5 High-Level API reference pages to nav bar.
    Added quick-links bar for
        High-level APIs
        Main HDF5 Library, including Low-level APIs
        Fortran and C++ Interfaces
    Added "Main HDF5 Library, including Low-level APIs" heading.
        There had previously been no comparable heading.
Platforms tested:
    Firefox