update

git-svn-id: svn+ssh://svn.internal.sanger.ac.uk/repos/svn/pathsoft/artemis/trunk@7137 ee4ac58c-ac51-4696-9907-e4b3aa274f04

ChangeLog

 Version ??
 
-	Add redo function to 'Edit' menu
+	Add redo function to 'Edit' menu. Also enable/disable undo and
+	redo menu items when available/not available.
 	
 	Add option to replace selected bases in 'Edit' menu.