support for packaged e-resource materials.
add statement_of_responsibility even if there is no description on the note field.
Update spec/fixtures (CarrierTypes and ContentTypes). cf. next-l/enju_leaf#300
CarrierType updated.
Update mappings for ContentType and CarrierType. see next-l/enju_leaf#328
add spec for notated music.
Display ISBN field in the search results.
Merge pull request #3 from masao/1.1

Supports new ContentType, CarrierType