[SPARK-6782] add sbt-revolver plugin

to make it easier to start & stop http servers in sbt
https://issues.apache.org/jira/browse/SPARK-6782

Author: Imran Rashid <irashid@cloudera.com>

Closes apache#5426 from squito/SPARK-6782 and squashes the following commits:

dc4fb19 [Imran Rashid] add sbt-revolved plugin, to make it easier to start & stop http servers in sbt

project/SparkBuild.scala

@@ -27,6 +27,8 @@ import sbtunidoc.Plugin.UnidocKeys.unidocGenjavadocVersion
 import com.typesafe.sbt.pom.{loadEffectivePom, PomBuild, SbtPomKeys}
 import net.virtualvoid.sbt.graph.Plugin.graphSettings
 
+import spray.revolver.RevolverPlugin._
+
 object BuildCommons {
 
   private val buildLocation = file(".").getAbsoluteFile.getParentFile
@@ -159,7 +161,7 @@ object SparkBuild extends PomBuild {
   // Note ordering of these settings matter.
   /* Enable shared settings on all projects */
   (allProjects ++ optionallyEnabledProjects ++ assemblyProjects ++ Seq(spark, tools))
-    .foreach(enable(sharedSettings ++ ExludedDependencies.settings))
+    .foreach(enable(sharedSettings ++ ExludedDependencies.settings ++ Revolver.settings))
 
   /* Enable tests settings for all projects except examples, assembly and tools */
   (allProjects ++ optionallyEnabledProjects).foreach(enable(TestSettings.settings))

project/plugins.sbt

@@ -29,6 +29,8 @@ addSbtPlugin("com.eed3si9n" % "sbt-unidoc" % "0.3.3")
 
 addSbtPlugin("com.cavorite" % "sbt-avro" % "0.3.2")
 
+addSbtPlugin("io.spray" % "sbt-revolver" % "0.7.2")
+
 libraryDependencies += "org.ow2.asm"  % "asm" % "5.0.3"
 
 libraryDependencies += "org.ow2.asm"  % "asm-commons" % "5.0.3"