+ newrelic: Report NewRelic error with correct URI and closes #103
= kamon-datadog: fix typo
+ statsD: include ContextSwitchesMetrics
+ datadog: include ContextSwitchesMetrics
! newrelic: major refactor of the newrelic reporter

Most notable changes:
  - The agent connection setup is separated from the actual metrics reporting,
    this will be important in the near future when we start sending errors too.
  - The metrics subscriptions are delayed until the connection to the agent is
    established.
  - The Tick metrics buffer is only created if necessary.
  - Introduced the kamon.newrelic.max-initialize-retries and initialize-retry-delay
    settings.
  - External service calls via HTTP clients are reported as external services.
= spray: fix a incorrect trace token mismatch warning introduced by a recent refactor
! spray: correcly provide http-client segment names based on the request host.
= core,play: workaround the non thread safe calls to TrieMap.getOrElseUpdate
= core,spray,newrelic: minor formatting changes.
= core: ensure that ActorMetricsSpec uses the correct configuration.
Merge branch 'wip/newrelic-agent-rewrite'
! build: only depend on aspectjweaver with provided scope, closes #106
+ core,play,spray: allow segments to identify the library they belong to.
+ newrelic: report additional and scoped external service metrics, improves #63.
Merge branch 'master' into release-0.2

Conflicts:
	kamon-newrelic/src/main/scala/kamon/newrelic/Agent.scala
	kamon-newrelic/src/main/scala/kamon/newrelic/NewRelic.scala
	kamon-play/src/main/scala/kamon/play/instrumentation/WSInstrumentation.scala
	project/Dependencies.scala
	project/Projects.scala
include missing files from previous commit.