h4h5tools

Make h4h5tools to link both 1.6 and 1.8. 
1.8 has updated a few APIs that makes h4h5tools fail to compile.
The check-in makes sure h4h5tools can link with both 1.8 and 1.6 by defining a few macros to cover API changes(H5Gopen etc.).


Tested at kagiso for both 1.6 and 1.8.