item-level itemtypes issuingrules require some testing.

item-level itemtypes issuingrules require some testing.

based on syspref 'item-level_itypes', add an itype col to items table
for 3.2 itype's type will change from varchar(10) to int to allow
circ type definitions per agency.
Note that updatedatabase doesn't populate items.itype, just creates column.

Signed-off-by: Chris Cormack <crc@liblime.com>
Signed-off-by: Joshua Ferraro <jmf@liblime.com>