Improvements overall to Nu. Also among the changes here, we can also be more confident towards incorporating `3041`. End to end tests for checking envs properly exported to externals is not added here (since it's in the other PR)
A few things added in this PR (probably forgetting some too)
* no writes happen to history during test runs.
* environment syncing end to end coverage added.
* clean up / refactorings few areas.
* testing API for finer control (can write tests passing more than one pipeline)
* can pass environment variables in tests that nu will inherit when running.
* No longer needed.
* no longer under a module. No need to use super.
* Move run_script to engine
* Add which dep and feature to engine
* Change unwrap to expect
* Add wasm specification
* Remove which from default, add specification correctly
* Add nu-platform-specifics
* Move is_external_cmd to platform_specifics
* Add is_external_cmd to host and use it instead of nu_platform directly
* Clean up if else logic in is_external_cmd
* Bump nu-platform-specifics version
* Pass context to print_err
* Commit cargo.lock
* Move print functions to own module inside nu-engine
* Hypocratic change to run windows-nightly again
* Add import for Ordering
* Move printing of error to host
* Move platform specific which functionality to basic host
* Allow no use of cmd_name
* Fix windows compile issue
* move commands, futures.rs, script.rs, utils
* move over maybe_print_errors
* add nu_command crate references to nu_cli
* in commands.rs open up to pub mod from pub(crate)
* nu-cli, nu-command, and nu tests are now passing
* cargo fmt
* clean up nu-cli/src/prelude.rs
* code cleanup
* for some reason lex.rs was not formatted, may be causing my error
* remove mod completion from lib.rs which was not being used along with quickcheck macros
* add in allow unused imports
* comment out one failing external test; comment out one failing internal test
* revert commenting out failing tests; something else might be going on; someone with a windows machine should check and see what is going on with these failing windows tests
* Update Cargo.toml
Extend the optional features to nu-command
Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
