Bug 10692: add unit tests for C4::Circulation routines about transfers

The tests are wrap in a transaction.

NOTE: Currently, some tests should pass but don't because of incoherences in the code.
These tests are in comments and preceded by FIXME.

To test:
prove t/db_dependent/Circulation_transfers.t
t/db_dependent/Circulation_transfers.t .. ok
All tests successful.
Files=1, Tests=12, 18 wallclock secs ( 0.02 usr  0.01 sys +  0.37 cusr  0.06 csys =  0.46 CPU)
Result: PASS

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>