vchoi_fork

[svn-r13120] Description:
	Add support for deleting deleting dense storage when no compact
storage will be used.

	Change shared message's "get heap address" routine to return
address in parameter instead of return value, to allow better error
detection.

	Start writing tests for shared attributes which use shared 
components (datatypes or dataspaces)

Tested on:
	Mac OS X/32 10.4.8 (amazon)
	FreeBSD/32 6.1 (duty)