Bug 13495: Use "checked in" instead of "returned" in circulation

Bug 13495: Use "checked in" instead of "returned" in circulation

To test:
- check out one or many items on a patron account
- return the items from the checkout table
- notice that a message "Checked in" is now shown
  in the first and last column, instead of "Returned"
  as before

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
I feel dirty signing this off, but I guess we have to be consistent in
our language

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Fixed merge conflict by removing changed lines no longer needed.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>