correct typo challenge 4

change 'ot kolkoto' to 'otkolkoto'
Merge pull request #30 from lpapazow/chellenge-04-fix-typos

correct typo challenge 4
Add challenge 05's full spec and our solution
Use .md as an extension for Markdown files
Add task 4
Merge remote-tracking branch 'upstream/master'
my solution to challenge 05