LP 1779467: Enhance Mark Items Functionality

LP 1779467: Enhance Mark Items Functionality

A new option to "Mark Item as Discard/Weed" is added to many actions
menus in the staff client.  This command is connected to the back end
function open-ils.circ.mark_item_discard.

The back end functionality for the open-ils.circ.mark_item_* family of
functions is altered to provide more consistent behavior and to avoid
some strange situations that have come up in the past, such as items
with the Missing status having active transits or open circulations.

The code for "Mark Item as Damaged" and "Mark Item as Missing" are
altered to take advantage of the back end changes.  NB: These changes
do not affect the "Mark Item as Missing Pieces" function, as that is
handled by different back end code.

Perl live tests are added for the backend functionality changes to
test that certain conditions works.  Like most of our tests these
could be expanded to cover more potential situations.

See the release notes for more detail on changes in functionality.

Signed-off-by: Jason Stephenson <jason@sigio.com>