* Utility function to detect hidden folders.
Implemented for Unix and Windows.
* Rename function argument.
* Revert "Rename function argument."
This reverts commit e7ab70f0f0.
* Add flag '--all/-a' to Ls
* Rename function argument.
* Check if flag '--all/-a' is present and path is hidden.
Replace match with map_err for glob result.
Remove redundancy in stream body.
Included comments on new stream body.
Replace async_stream::stream with async_stream::try_stream.
Minor tweaks to is_empty_dir.
Fix and refactor is_hidden_dir.
* Fix "implicit" bool coerse
* Fixed clippy errors
This improves incremental build time when working on what was previously
the root package. For example, previously all plugins would be rebuilt
with a change to `src/commands/classified/external.rs`, but now only
`nu-cli` will have to be rebuilt (and anything that depends on it).
