In Scrivener 2, you could Option+drag a document into the Editor to create a link to it in the text. Now, you can simply drag and drop the document into the text to create a link. Not up for dragging and dropping? An alternative is Edit>Link to Document.
Option+dragging a file into the text area of the Editor will now add the contents of the document wherever you release it in the Editor. CAUTION: In my experience, Edit>Undo does not work with option+dragging the contents of a file, so be careful.