How to not import/duplicate media in FCPX? When I create a new Event and Project within it, I don't see a way to avoid copying imported media to the FCPX folder (apparently there used to be an option when creating a new Event to not copy imported media, but it doesn't appear to be there any longer).

How can I do that? By the way, I'm importing from the Photos library browser within FCPX if that makes any difference.
For FCPX 10.1 and later:

Open preferences
Select the import tab
Choose to either leave Files in Place or Copy to Storage Library Location.

To set the Storage Library Location:

Select the library. 
Open the inspector.
Select Modify Settings in the inspector to choose where your generated files go.