challenge 04: update README
challenge 04: fix typos
challenge 04: add one more sample test to enhance the readability
Merge pull request #14 from tochev/challenge_04_fixes

Challenge 04 fixes
challenge 04: add tests and solution
challenge 04: fix tests
Add solution and tests for challenge 03.
Merge branch 'master' of github.com:fmi/clojure-homework
Fix deftest name of the tests of challenge 03.