* update docs to refer to length instead of count
* rename count to length
* change all occurrences of 'count' to 'length' in tests
* format length command
`drop` is used for removing the last row. Passing a number allows dropping N rows.
Here we introduce the same logic for dropping columns instead.
You can certainly remove columns by using `reject`, however, there could be cases
where we are interested in removing columns from tables that contain, say, a big
number of columns. Using `reject` becomes impractical, especially when you don't
care about the column names that could either be known or not known when exploring
tables.
```
> echo [[lib, extension]; [nu-core, rs] [rake, rb]]
─────────┬───────────
lib │ extension
─────────┼───────────
nu-core │ rs
rake │ rb
─────────┴───────────
```
```
> echo [[lib, extension]; [nu-core, rs] [rake, rb]] | drop column
─────────
lib
─────────
nu-core
rake
─────────
```
* 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>
