do shippedDate empty
Merge remote-tracking branch 'origin/master' into RailcarShippedDate
add search railcar by shipping date
remove DeliveryDate from Railcar
make Railcar ShippingDate nullable
fix Railcar <-> Pipe maping
fix PipeMillSizeType in Pipe
ship / unship in one button
Merge remote-tracking branch 'origin/master' into RailcarShippedDate

Conflicts:
	src/Data/DAL/Mapping/PipeMap.cs
	src/Data/DAL/Mapping/RailcarMap.cs
	src/PrizmMainProject/Properties/licenses.licx
Merge from master
Merge pull request #207 from olga-jane/RailcarShippedDate

Railcar Shipped Date