* Fix and refactor cd for Filesystem Shell.
Reorder check conditions, don't check existence twice.
If building for unix check exec bit on folder.
* Import PermissionsExt only on unix target.
* It seems that this is the correct way?
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).
In particular, one thing that we can't (properly) do before this commit
is consuming an infinite input stream. For example:
```
yes | grep y | head -n10
```
will give 10 "y"s in most shells, but blocks indefinitely in nu. This PR
resolves that by doing blocking I/O in threads, and reducing the `await`
calls we currently have in our pipeline code.
* Create a function to create an empty directory entry
* Print an empty directory entry if permission is denied
* Fix rustfmt whitespace issues.
* Made metadata optional for `dir_entry_dict`.
Removed `empty_dir_entry_dict` as its not needed anymore.
* Add very basic documentation. Need to play with rest of the api to figure out what it does
* Add some documentation to more of the Plugin API methods
* fmt
* typo fixes
* Change signature to take in short-hand flags
* update help information
* Parse short-hand flags as their long counterparts
* lints
* Modified a couple tests to use shorthand flags
* Add block size to du
* Change blocks to physical size
* Use path instead of strings for file/directory names
* Why don't I just use paths instead of strings anyway?
* shorten physical size and apparent size to physical and apparent resp.
* Add some docs for meta.rs
* add better explanation for Span merging
* Add some doc tests - not sure how to get them to run
* get rid of doc comments for the temporary method
* add doc test for is_unknown
* fmt
* Refactor pipeline ahead of block changes. Add '-c' commandline option
* Update pipelining an error value
* Fmt
* Clippy
* Add stdin redirect for -c flag
* Add stdin redirect for -c flag
