Migrated SIP-14 Futures from scalaz-contrib

Moved SIP-14 Future instances from scalaz-contrib to
scalaz-{core, effect}. Everything minus `forkIO` is in
`core`, `forkIO` is in effect.
removed deprecated Each instance for Future
renamed future to scalaFuture in effect
migrated tests for SIP-14 Future
Merge pull request #560 from adelbertc/sip14

Migrated SIP-14 Futures from scalaz-contrib