Upgrade to Akka 2.2-M2, remove akka.io sources from spray-io module

 After this upgrade we have three failing tests due to smaller problems in akka-io 2.2-M2, which will be fixed for Akka 2.2-M3.
Merge branch 'master' into release-1.2.x

Conflicts:
	spray-io/src/main/scala/akka/io/DirectByteBufferPool.scala
	spray-io/src/main/scala/akka/io/IO.scala
	spray-io/src/main/scala/akka/io/SelectionHandler.scala
	spray-io/src/main/scala/akka/io/Tcp.scala
	spray-io/src/main/scala/akka/io/TcpConnection.scala
	spray-io/src/main/scala/akka/io/TcpIncomingConnection.scala
	spray-io/src/main/scala/akka/io/TcpListener.scala
	spray-io/src/main/scala/akka/io/TcpManager.scala
	spray-io/src/main/scala/akka/io/TcpOutgoingConnection.scala
	spray-io/src/main/scala/akka/io/Udp.scala
	spray-io/src/main/scala/akka/io/UdpConnected.scala
	spray-io/src/main/scala/akka/io/UdpConnectedManager.scala
	spray-io/src/main/scala/akka/io/UdpConnection.scala
	spray-io/src/main/scala/akka/io/UdpListener.scala
	spray-io/src/main/scala/akka/io/UdpSender.scala
	spray-io/src/main/scala/akka/io/WithUdpSend.scala
Merge remote-tracking branch 'origin/master' into release-1.2.x
Merge remote-tracking branch 'origin/master' into release-1.2.x

Conflicts:
	spray-io/src/main/scala/akka/io/IO.scala
	spray-io/src/main/scala/akka/io/Inet.scala
	spray-io/src/main/scala/akka/io/SelectionHandler.scala
	spray-io/src/main/scala/akka/io/Tcp.scala
	spray-io/src/main/scala/akka/io/TcpConnection.scala
	spray-io/src/main/scala/akka/io/TcpIncomingConnection.scala
	spray-io/src/main/scala/akka/io/TcpListener.scala
	spray-io/src/main/scala/akka/io/TcpManager.scala
	spray-io/src/main/scala/akka/io/TcpOutgoingConnection.scala
	spray-io/src/main/scala/akka/io/Udp.scala
	spray-io/src/main/scala/akka/io/UdpConnected.scala
	spray-io/src/main/scala/akka/io/UdpConnectedManager.scala
	spray-io/src/main/scala/akka/io/UdpConnection.scala
	spray-io/src/main/scala/akka/io/UdpListener.scala
	spray-io/src/main/scala/akka/io/UdpManager.scala
	spray-io/src/main/scala/akka/io/UdpSender.scala
	spray-io/src/main/scala/akka/io/WithUdpSend.scala
sbt: upgrade to Akka 2.2.0-RC1
Merge remote-tracking branch 'origin/master' into release-1.2.x
Merge remote-tracking branch 'origin/release/1.1' into release-1.2.x
docs & site: upgrade to 1.2
Prepare for 1.2-M8 release
Merge remote-tracking branch 'origin/master' into release/1.2
Merge remote-tracking branch 'origin/master' into release/1.2
Merge remote-tracking branch 'origin/master' into release/1.2
Merge remote-tracking branch 'origin/master' into release/1.2
Merge remote-tracking branch 'origin/master' into release/1.2
= sbt: upgrade to Akka 2.2.0-RC2
Merge remote-tracking branch 'origin/master' into release/1.2
= sbt: upgrade to Akka 2.2.0 final
Merge remote-tracking branch 'origin/master' into release/1.2
Added initial class files for Hawk authentication
+ routing: Add MAC computation logic to HawkAuthenticator