Akka streams 2 upgrade

[fsat]

Migrate to Akka Streams and HTTP 2.0-M2

• Implement necessary modification to support Akka Streams and HTTP 2.0-M2
• Remove support for Java 6

[huntc]

Please squash commits - also - check out the new input/output stream publishers of akka streams. We probably don't need ours anymore?

[fsat]

Can I get the class names for these actors please?

I've checked the docs and API dos, and I can't seem to find the replacement equivalent of the Input/Output stream publisher out-of-the-box within Akka streams 2.0-M2.

[huntc]

I don't know if these are good fits, but there exists InputStreamSource and OutputStreamSink.

[fsat]

Are you referring to Source.inputstream()

def inputStream(in: () ⇒ InputStream, chunkSize: Int = 8192): Source[ByteString, Future[Long]]

and Sink.outputstream()

def outputStream(out: () ⇒ OutputStream): Sink[ByteString, Future[Long]]

If these are the ones you have in mind, we will need to deprecate the InputStreamSubscriber and OutputStreamPublisher within the akka-contrib-extra, and so the caller can change accordingly (i.e. change LoadExecutor in ConductR to use Source.inputstream() instead.)

[fsat]

Travis build failed due to openjdk6 crashing - I'm still trying to find how to obtain openjdk6

[ktoso]

LGTM so far

[fsat]

@ktoso - thanks for the PR review :-)

[ktoso]

LGTM, nice :+1: