[svn-r19401] Purpose:

Fix for Bug1975 h5diff - support recursive comparison on group when specified as an object

Description:
 Merged from hdf5 trunk (r19400).
 Compare member objects and groups recursively when two files or groups are specified to be compared. Support parallel diff and handling symbolic links accordingly.

Tested:
 jam, amani

tools/h5diff/testfiles/h5diff_510.txt

@@ -0,0 +1,32 @@
+
+group1   group2
+---------------------------------------
+    x      x                   
+    x      x    /dset1         
+    x      x    /grp2          
+    x      x    /grp2/dset1    
+    x      x    /grp2/dset2    
+    x      x    /grp2/grp3     
+    x      x    /grp2/grp3/dset1
+    x      x    /grp2/grp3/dset2
+    x      x    /grp2/grp3/dset3
+
+group  : </slink_grp1> and </elink_grp1>
+0 differences found
+dataset: </slink_grp1/dset1> and </elink_grp1/dset1>
+0 differences found
+group  : </slink_grp1/grp2> and </elink_grp1/grp2>
+0 differences found
+dataset: </slink_grp1/grp2/dset1> and </elink_grp1/grp2/dset1>
+0 differences found
+dataset: </slink_grp1/grp2/dset2> and </elink_grp1/grp2/dset2>
+0 differences found
+group  : </slink_grp1/grp2/grp3> and </elink_grp1/grp2/grp3>
+0 differences found
+dataset: </slink_grp1/grp2/grp3/dset1> and </elink_grp1/grp2/grp3/dset1>
+0 differences found
+dataset: </slink_grp1/grp2/grp3/dset2> and </elink_grp1/grp2/grp3/dset2>
+0 differences found
+dataset: </slink_grp1/grp2/grp3/dset3> and </elink_grp1/grp2/grp3/dset3>
+0 differences found
+EXIT CODE: 0