tail.rs: Replace deprecated rust code.

See merge request !1

Misc fixes: Lockfile update and disabling stat

See merge request redox-os/coreutils!201

It's currently build-broken. Let's allow the rest of the utils build for
the moment.

Was referring to an old syscall crate version. Update needed to build
for AArch64.

integrate failure crate and redo error system

See merge request redox-os/coreutils!199

Add postfixes to numbers in dd

See merge request redox-os/coreutils!197

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`.