hdf5_msb

[svn-r3199] 
Purpose: bug fix

Description:
	I found a couple of places where virtual destructors were missing
	and could cause small memory leaks.  Also, some destructors were
	not virtual when they should be.

Solution:
	- added virtual destructors, which also free dynamically allocated
	  memory
	- added virtual to several destructors
	- also, fixed several typos

Platforms tested:
	Solaris 2.7 (arabica)