Incorparate review feedback, see #2547

* case object and case class for MixMetricsSelector
* Rename decay-half-life-duration to moving-average-half-life
* Clarification of decay-half-life-duration and collect-interval
* Removed Fields, Java compatibility issue
* Adapt for-yield variables
* Comment metrics collector constructor that takes system param
* Don't copy EWMA if not needed
* LogOf2 constant 0.69315
* Don't use mapValues
* Remove RichInt conversion
* sigar version replace tag in docs
* createDeployer factory method to make it possible to override
  deployer in subclass
* Improve readability of MetricsListener (in sample)
* Better startup of factorial sample (no sleep)
* Many minor enhancements and cleanups

akka-cluster/src/multi-jvm/scala/akka/cluster/routing/AdaptiveLoadBalancingRouterSpec.scala

@@ -131,10 +131,10 @@ abstract class AdaptiveLoadBalancingRouterSpec extends MultiNodeSpec(AdaptiveLoa
         val router1 = startRouter("router1")
 
         // collect some metrics before we start
-        Thread.sleep(10000)
+        Thread.sleep(cluster.settings.MetricsInterval.toMillis * 10)
 
         val iterationCount = 100
-        for (i ← 0 until iterationCount) {
+        1 to iterationCount foreach { _ ⇒
           router1 ! "hit"
           // wait a while between each message, since metrics is collected periodically
           Thread.sleep(10)