Use the Scala wrapper for System.getProperty that returns Option.
Use stdlib's Future.zip for parallel Future execution.

Stdlib Future's already have a .zip method that executes them both in
parallel.
Cons: A useless intermediate tuple.
Merge pull request #577 from LeifW/use_future_zip

Use future zip
remove `implicit` modifier from `fromScalaOrdering`

Closes #358.
Crush OptionT Apply and Applicative into Monad; make its ap sane.
Crush LazyOptionT Apply and Applicative into Monad; make its ap sane.
Merge pull request #581 from S11001001/topic/optiont-ap-bind-legal

Make OptionT/LazyOptionT monad legal in ap/bind consistency