[svn-r22105] Description:

Bring r20557:22085 from trunk to this branch, also fixing some other
issues/failures in the branch simultaneously.  The h5repack tests are still
failing, but Neil will be checking into those, so the branch can be fully
functional again.

Tested on:
	Mac OSX/64 10.7.3 (amazon) w/debug

tools/h5diff/testfiles/h5diff_30.txt

@@ -0,0 +1,9 @@
+dataset: </dset1> and </dset2>
+size:           [6]           [6]
+position        dset1           dset2           difference          
+------------------------------------------------------------
+[ 1 ]          YIN              **INVALID VALUE**
+[ 2 ]          **INVALID VALUE** YIN              
+[ 5 ]          YIN              YANG             
+3 differences found
+EXIT CODE: 1