v1.6.1

Added

• asSet() for array and strings (#1)
• occurrencesOf(object) for array and strings (#2)
• includesAllOf(collection) for arrays and strings (#3)
• Add existing messages to Set, which is a collection (#4)
• forEach() for strings (#6)
• equals() for strings (#8)
• Messages on Set to have more polymorphism: filter, includes, equals, asSet