Bug 16486: Display the timestamp when an accountline is updated

Bug 16486: Display the timestamp when an accountline is updated

This patch updates the Date field to be 'Created' and adds a new column
'Updated' which shows the timestamp of the accountline.

To test:
1) Apply patch, restart services
2) Test the following staff client pages:
- Reports -> Cash register
- Patron Accounting tab -> Transactions
- Create a manual invoice. Click 'Print' on the transactions tab to
generate Invoice slip
- Make a payment. Click 'Print' on the transactions tab to generate
Receipt slip
3) Test the OPAC:
- your charges

Sponsored-by: Catalyst IT
Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>