Fix for #41 - Directories are shown as empty

[Gerdal]

Unfortunatelly now app is scanning only root directory so this is why it can't find files in subdirectories. Probably there is possible to rewrite it to don't run scan on every directory change but this will need more investigation.

[beerfranz]

Hi! Thanks for the patch, but it doesn't fix the bug. In nextcloud log when I try to add a file in a sub directory: "File not found: foo.md.ocTransferId337113781.part"

File part is put in my gdrive in foo/foo.md.ocTransferId337113781.part