Log Message:
Update to 5.71:

5.71  Wed Feb 29 04:06:10 MST 2012
	- prevented $! from getting clobbered in _bail() routine
		-- thanks to Zefram for patch
	- added example of BITS mode usage to shasum documentation

5.70  Wed Dec 14 02:32:10 MST 2011
	- added BITS mode to addfile method and shasum
		-- partial-byte inputs now possible via files/STDIN
		-- allows shasum to check all 8074 NIST Msg vectors
			-- previously required special programming

5.63  Tue Nov  8 02:36:42 MST 2011
	- added code to allow very large data inputs all at once
		-- previously limited to several hundred MB at a time
		-- many thanks to Thomas Drugeon for his elegant patch
	- removed outdated reference URLs from several test scripts
		-- these URLs aren't essential, and often go stale
		-- thanks to Leon Brocard for spotting this
			-- ref. rt.cpan.org #68740