Update documentation/manual/scalaGuide/advanced/iteratees/Iteratees.md

Changed from Promise to scala Future fixed issues with codes.
Update documentation/manual/scalaGuide/advanced/iteratees/Iteratees.md

Minor: Comment added.
Update documentation/manual/scalaGuide/advanced/iteratees/Enumeratees.md

Fixing typos and changes for scala futures. Made sure that code compiles and run.
Merge pull request #653 from ratulb/master

Changed from Promise to scala future and fixed issues with code.