test integration with 3rd party app: jupyter-fs

[telamonian]

The tree-finder UI is starting to mature and is now mostly feature complete.

The next thing to build in tree-finder will be support for commands (cut, copy, paste, open, etc). I think the easiest way to design these will be trial-by-fire: I'll take an app with an existing filebrowser UI, and existing backend implementations for commands, and try out the current tree-finder as a drop-in replacement.

The first target will be jupyter-fs

[telamonian]

first live prototype of new Jupyter filebrowser UI achieved! There's now a functional example of a tree-finder-panel plugged into an actual Jupyter ContentsManager backend:

[telamonian]

As of jupyter-fs v0.3.0, the filebrowser in jupyter-fs is now powered by tree-finder, including a context menu powered by a bunch of command hooks also supplied by tree-finder