Merge pull request #39 from stanislaw/master

Prefer machine way of doing even/odd checks
Shared scheme.
Fixed #40.
Update README.md
Better count occurrences of each element in array (#40, #41).

- Adds -[NSArray(EKStuff) occurencesOfEachElementInArrayByUsingDictionary] which is more efficient than original occurencesOfEachElementInArray.
- BDD for #40