Add support for async Netty intents using Scala futures
deprecate the redundant Directive.success
Merge pull request #176 from daggerrz/feature/scala-futures

Add support for async Netty intents using Scala futures
spacing
General kit for response functions of future, and moving `FuturePlan`
into a `future` package.
this stack trace should be printed to stderr too
actually respond with the error
rework Futured kit so we can use the plan's configured exception handler
Merge branch 'master' into unified

Conflicts:
	directives/src/main/scala/directives/Directive.scala
	directives/src/main/scala/directives/Directives.scala