Add other FP iterators / utilities

[Kyle Simpson]

Going through the list of methods in FPO, I think we probably should add serial/concurrent versions (where applicable) of these:

• flatMap(..)
• pipe(..) (using reduce(..))
• compose(..) (using reduceRight(..))
• filter(..) alias to filterIn(..)
• filterOut(..) (the inverse of filter(..))
• transducers? need to research what, if anything, this would look like for fasy