Clear hierarchy of import order

[mebrett]

This is less of a bug than double checking expected behavior so I can be clear in the documentation.

I had a CSV with a column for "owner" (meaning item owner's email address), but for that import I checked automapping for both property labels and user data. Turns out the owner column mapped to bibo:owner, rather than user data (item owner). Easy enough to fix manually, but I wanted to be clear that property labels will be mapped first, then user data, so that I can make sure that's mentioned in the documentation.

[Daniel-KM]

The automapping mechanism tries the properties first, then the single labels of properties if the option is set, then the current user automapping if the option is set. There is no other automapping. Note that in the list of headers for the current user automapping, the header "owner" is managed by default.