Update README.md
Fix build with latest Rust compiler.
Implement echo
Remove echo from README
Refactoring
Merge pull request #13 from derekchiang/patch-1

Add a contribution guide
Merge pull request #15 from KokaKiwi/fix-build

Fix build with latest Rust compiler (yeah, again)
Merge branch 'master' of github.com:uutils/coreutils into add-echo
Refactoring
Merge pull request #16 from derekchiang/add-echo

Implement echo
reduce merge pain of Makefile
Merge pull request #18 from ashleyh/master

reduce merge pain of Makefile
rust println supports multi-line ...
Merge pull request #23 from Heather/master

rust println supports multi-line ...