LP#1356477: add quick receipt button

LP#1356477: add quick receipt button

This patch adds a new button to the webstaff checkout page
called Quick Receipt. If the button itself is pushed, a
receipt containing the current checkouts is either printed
or emailed, depending on the user's preference. If the
drop-down portion of the button is used, staff members can
override the user's default preference to print or email
the receipt.

The Quick Receipt button is enabled only if at least one
checkout has been made during the current session.

Note that email receipts is an option only when the patron
has an email address supplied.

An icon next to the Quick Receipt button will be either a
printer or an envelope depending on the user's preferred
receipt setting.

This patch also modifies the "Done" button. If pressed, the session
is ended and the receipt is generated according to the user's
preferences, but the drop-down portion can be used to end
the session while letting the staff member choose how the
receipt is emitted.

If a receipt is emailed, a toast is displayed saying so.

Signed-off-by: Mike Rylander <miker@esilibrary.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>