updated for version 7.4.399
Problem:    Encryption implementation is messy.  Blowfish encryption has a
	    weakness.
Solution:   Refactor the encryption, store the state in an allocated struct
	    instead of using a save/restore mechanism.  Introduce the
	    "blowfish2" method, which does not have the weakness and encrypts
	    the whole undo file. (largely by David Leadbeater)
Added tag v7-4-399 for changeset 18ac55444b37
updated for version 7.4.400
Problem:    List of distributed files is incomplete.
Solution:   Add recently added files.
Added tag v7-4-400 for changeset 50a658bf4cff
updated for version 7.4.401
Problem:    Can't build on MS-Windows.
Solution:   Include the new files in all the Makefiles.
Added tag v7-4-401 for changeset ab71bb81b84e