v1.1.9

• Added custom operators for Optionals (thanks to @dr-projectiro for suggestion)
• Added filterNot for Optionals
• Added Stream.merge operator (thanks to @landawn)
• Added Stream.concat for iterators
• Added Stream.ofNullable for array, map and iterator (thanks to @petnagy)
• Added Collectors.partitioningBy
• Added getOrElse(Supplier), isPresent and custom operators support for Exceptional (thanks to @PromanSEW)