Folders

Folder add, navigate, edit, and delete all implemented.

All actions via icons.

There are some things that could be better:
* I've confirmed that the deletion actions on the proper crypton objects happens with delete, but we should have tests for that (and everything else...)
* The screen locations of the icons needs to be fixed - I'm leaving that to @devgeeks.
* When adding within a folder, it would be good to indicate at least the end of the path.
* When editing a folder, the screen title is empty - it should be "Folder".