First cut at attempting to track State all the way through.

* DO NOT drop a State instance, EVER!
* Remove "bad" methods from SbtUtil.
* Add new, dumber methods.
Merge pull request #109 from sbt/wip/henrik-jsuereth-fix-play-23-leaky-state

First cut at attempting to track State all the way through.
Added basics for new relic discovery
Added tests to detect existence/absence of New Relic agent
Expanded NewRelic support to deliver the patch to the artifact
Merge branch 'new-relic-discovery' of github.com:sbt/sbt-remote-control into new-relic-discovery

Conflicts:
	commons/protocol/src/main/scala/com/typesafe/sbtrc/io/ShimWriter.scala
	integration-tests/src/main/scala/com/typesafe/sbtrc/CanDiscoverNewRelicPlay21Sbt12Project.scala
	integration-tests/src/main/scala/com/typesafe/sbtrc/CanDiscoverNewRelicPlay22Sbt13Project.scala
	probe/0.12/probe/src/main/scala/com/typesafe/sbtrc/controller/DefaultsShim.scala
	probe/0.12/probe/src/main/scala/com/typesafe/sbtrc/controller/NewRelicSupport.scala
	probe/0.13/probe/src/main/scala/com/typesafe/sbtrc/controller/DefaultShim.scala
	probe/0.13/probe/src/main/scala/com/typesafe/sbtrc/controller/NewRelicSupport.scala