Add my solution and test to the fifth challenge.
challenge 05: improvements
challenge 05: typo
Merge branch 'master' into my-solutions

Conflicts:
	challenges/05/sample_test.clj
Update my solution and tests of the fifth challenge according to the new statement.
task 04: pattern matching
task 04: or -> :or
task 04: add bonus notes
task 04: remove keywords from examples
challenge 05: add tests and solution
task 04: clarify
task 04: tweak
Merge branch 'master' into my-solutions