BUGFIX in order canEdit and improved packing slip

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/trunk@5152 950b781c-c544-efab-2f99-90083ee69683
ENHANCEMENT: emogrifier; BUGFIX: hasBeenSent; 

git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/trunk@5153 950b781c-c544-efab-2f99-90083ee69683
git-svn-id: https://silverstripe-ecommerce.googlecode.com/svn/trunk@5154 950b781c-c544-efab-2f99-90083ee69683