Add folders to compendium import

[ironmonk108]

v11 has added folders to the compendium structure. And code should be added to check for, and use that structure.
This way other users could take advantage of the library browser.

[rikmarais]

This does appear to still be an open issue after the changes in 1.4.1.
259744a does reference the compendium folder structure in the new documentation.