[svn-r16670] Interrim checkin of journal file modifications supporting recognition

and rejection of attempts to apply the wrong journal file to a corrupt
HDF5 file.  Specifically, I made the following changes:

1) Moved all journaling data into the journaling in progress superblock 
   extension message.

2) Added a "magic number" to the journaling in progress message, with 
   the same "magic number being added to the header of the associated 
   journal file.

3) Modifications to library test code to support the above.

4) Modified h5recover to examine the supplied hdf5 file, determine if 
   it is in fact a HDF5 file, if so determine if it is marked as having
   journaling in progress, and if it does, extract the contents of the
   journaling in progress super block extension message.

5) Modified h5recover to examine the supplied journal file, determine
   if it is in fact a HDF5 journal file, and if so, extract the data 
   from its header.

6) Modified h5recover to refuse to apply the supplied journal file to 
   the supplied HDF5 file unless the "magic numbers" obtained from these
   files matches.

7) Added an examine option to h5recover that causes it to examine and
   report on the supplied files, but do nothing.  This option exists 
   primarily to facilitate testing, but I expect that some users will
   find it useful as well.

8) Added test code to exercise items 4-7.  Note that while I have tried 
   to cover the more likely cases, this test code is extremely cursory.
   In particular, the code to examine the supplied HDF5 file is barely 
   tested at all.  Need a library of HDF5 files exibiting the full range
   of possible super block and super block extension message structures 
   to test this properly.  

9) In passing, tighened up the code that controls dumps of "possibly 
   significant" differences between the contents of the control and 
   recovered data sets in the h5recover.  It should now ignore one 
   integer matches in what appears to be garbage raw data.

Tested:  serial and parallel on Phoenix 
         serial and parallel on Jam
         serial on Linew
         serial on Liberty

         All tests were done in debug mode. 

1 files changed, 0 insertions, 0 deletions

diff --git a/test/testfiles/cache2_journal_sc00_005.jnl.gz b/test/testfiles/cache2_journal_sc00_005.jnl.gz
index c1550f0..964b907 100755
--- a/test/testfiles/cache2_journal_sc00_005.jnl.gz
+++ b/test/testfiles/cache2_journal_sc00_005.jnl.gz