Previously, if the user didn't have the appropriate permissions to execute the
binary/script, they would see "command not found", which is confusing.
This commit eliminates the `which` crate in favour of `ichwh`, which deals
better with permissions by not dealing with them at all! This is closer to the
behaviour of `which` in many shells. Permission checks are then left up to the
caller to deal with.
* WIP: move to bytes codec
* Progress on adding collect helpers
* Progress on adding collect helpers
* Add in line splitting back to lines
* Lines outputting line primitives
* Close to ready?
* Finish fixing lines
* clippy fixes
* fmt fixes
* removed unused code
* Cleanup a few bits
* Cleanup a few bits
* Cleanup a few more bits
* Fix failing test with corrected test case
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).
