Strong preservation law for Zip.
Remove Apply#zip; it yields unlawful Zip instances.
Zip symmetry law.
Merge branch 'scalaz-seven' of github.com:scalaz/scalaz into topic/zip-laws
Fix #489: pattern match in `Future.listen` is safe

`step` is guaranteed to remove `BindSuspend` and `Suspend`
optimize alignList
add These align unalign tests
add EphemeralStream#take, EphemeralStream#takeWhile
tests for EphemeralStream#take, EphemeralStream#takeWhile
Revert "Remove Apply#zip; it yields unlawful Zip instances."

This reverts commit e78e6a3c6656d476feb399052344b970f9ca7ef2.
Deprecate Apply#zip.
fix EphemeralStream#unzip type constraint
add EphemeralStream unzip zip test
Laws for Zip; deprecate Apply#zip. (#487)
zip laws test for Stream
Fix #371. Call-by-need instead of call-by-name.
Merge pull request #490 from xuwei-k/alignList

optimize alignList
Merge pull request #491 from xuwei-k/EphemeralStream-take-takeWhile

add EphemeralStream#take, EphemeralStream#takeWhile
Merge pull request #492 from xuwei-k/EphemeralStream-unzip

fix EphemeralStream#unzip type constraint