Update to use new redox_users API

Updating the readme to show only included files

Old readme included a list of executables long since vanished

Updated 'redox_users' and 'libextra' and used new APIs in there.

Performance improvement for cat without arguments

Performance improvement for cat with arguments (from 58 MB/s to 116 MB/s) by adding a 64KB input buffer, a 192KB output buffer and fixing a badly ordered if statement

dd: Fix status option

Signed-off-by: Jerome Jutteau <j.jutteau@gmail.com>

Simplify dd

Replaced unnecessary Input and Output structs by a Box<io::Read>

Signed-off-by: Jerome Jutteau <mojo@couak.net>

Migrated to `redox_users`.

Details:

- Using `redox_users` instead of `useutils`.
- Updated dependencies.
- Fixed some warnings in `tee`.
- Fixed formatting in `stat`.

'yes' shows invalid parameter error rather than silence 'y'

Ported changes from mv.rs to cp.rs

See title.

Reformatted, Restructured, Fix few bugs

* Fixed an edge case where the user could try to copy a directory onto a file
* Restructured the code to remove an unnecessary if clause and some unnecessary checks, thus causing a tiny performance increase
* Cntrl-Alt-L

Use released version of filetime

The new release works on Redox.

Remove chmod, env, and ls, which uutils has better versions of