Add Work Center to W/O Processing

[agaluski]

Currently a Work Center is added to BOM in BOM Maintenance but the W/O processing uses Location, not work center to determine which parts of the BOM to use. Ideally a work center should be assigned to a factory location and Work Orders assigned to a Work Center, not a location. The location will be assigned from the Work Center/Location reference. BOM Maintenance, cost calculations etc should use Work Center as part of the key in addition to location. The reason for this is that a product can be made differently on different manufacturing lines within the same factory.