Better subfolder-of-subfolder experience

[bhstahl]

Right now, when you share a subfolder of a subfolder, the user experience is a bit disjointed:

Tree:

/Partyshare/
└── books
    ├── Effective\ Go\ -\ The\ Go\ Programming\ Language.pdf
    └── react
        └── react-bits.pdf

App:

Come up with an ideal UX for these scenarios and implement it.

cc @Fil