Frans custom for Shipment module

Frans shipment has some custom.

1/ Shipment created vs shipment shipped

Shipping process goes like this: 
 - step 1 - Shipper creates a shipment
 - step 2 - Shipper adds packages to shipment
 - step 3 - Shipper adds products to shipment's packages
 - step 4 -Shipper prints label

Notice that after step 4; sales_shipment has column `ship_date` populated. Before step 4; `ship_date` is empty.

We use `sales_shipment` column `ship_date` to determine if and when the shipment ACTUALLY shipped. We call that column actual-ship-date. Do NOT use `sales_shipment` created_at column - that column only means that shipment begins (step 1).