Git commits in Moodle 1.9.7 by Francois Marier

commit 04a2ac065b36f6e787ece4cb559f51a735950a5b
Author: Francois Marier <francois@catalyst.net.nz>
Date:   Thu, 12 Nov 2009 09:58:05 +0800
Tag:    v1.9.7

MDL-20781 lib/excellib: add write_date() function