hdf5_ep

[svn-r2626] Purpose:
    New Feature
Description:
    Add -o option to h5dumper. It displays the raw data of datasets to a
    separate output file.
    Add a feature to h5tools library that it uses the FILE *rawdatastream
    as the stream for the display of datasets raw data.
Solution:
    Define an "extern FILE *rawdatastream" in h5tools.h
    and declare it in h5tools.c.  This way, it would work
    even if an application does not explicitely declare it.
    Tried to initialized it to stdout as
	FILE *rawdatastream = stdout;
    but Linux gcc rejected it though all other platforms+compilers
    accepted it fine.  For now, put in a kludge to set it right
    before it is used.  Need a safer way to initialize it.
Platforms tested:
    arabica, eirene, modi4 -64.