suggestion: add a function to simply collect recursivley the filenames in a directory

[andrewufrank]

I came to the package with a much simpler expectation - namely to collect the filenames recursively in a directory and build a tree structure (but without the content). I could not find anything else close. Collecting the file content is overkill for me, however I would love to have a ToJSON instance....

thank you!

[jberryman]

what would you like the ToJSON instance to look like?