hdf5

[svn-r24376] Updated all code to use HDmalloc, HDcalloc, and HDfree.

Prep work for adding a memory free function, part of HDFFV-8551.

Tested on:
    32-bit LE linux (jam) 
        * with C++, Fortran
        * with thread safety on

    These are minor changes (almost entirely renaming foo functions
    to HDfoo) that don't change functionality.  This should not
    require a full commit test.