add preprocessor for RST docs, see #2461 and #2431

The idea is to filter the sources, replacing @<var>@ occurrences with
the mapping for <var> (which is currently hard-coded). @@ -> @. In order
to make this work, I had to move the doc sources one directory down
(into akka-docs/rst) so that the filtered result could be in a sibling
directory so that relative links (to _sphinx plugins or real code) would
continue to work.

While I was at it I also changed it so that WARNINGs and ERRORs are not
swallowed into the debug dump anymore but printed at [warn] level
(minimum).

One piece of fallout is that the (online) html build is now run after
the normal one, not in parallel.

akka-docs/rst/scala/code/docs/routing/RouterViaConfigDocSpec.scala

@@ -0,0 +1,158 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.routing
+
+import akka.actor.{ Actor, Props, ActorSystem, ActorLogging }
+import com.typesafe.config.ConfigFactory
+import akka.routing.FromConfig
+import akka.routing.ConsistentHashingRouter.ConsistentHashable
+import akka.testkit.AkkaSpec
+import akka.testkit.ImplicitSender
+
+object RouterWithConfigDocSpec {
+
+  val config = ConfigFactory.parseString("""
+
+    //#config-round-robin
+    akka.actor.deployment {
+      /myrouter1 {
+        router = round-robin
+        nr-of-instances = 5
+      }
+    }
+    //#config-round-robin
+
+    //#config-resize
+    akka.actor.deployment {
+      /myrouter2 {
+        router = round-robin
+        resizer {
+          lower-bound = 2
+          upper-bound = 15
+        }
+      }
+    }
+    //#config-resize
+
+    //#config-random
+    akka.actor.deployment {
+      /myrouter3 {
+        router = random
+        nr-of-instances = 5
+      }
+    }
+    //#config-random
+
+    //#config-smallest-mailbox
+    akka.actor.deployment {
+      /myrouter4 {
+        router = smallest-mailbox
+        nr-of-instances = 5
+      }
+    }
+    //#config-smallest-mailbox
+
+    //#config-broadcast
+    akka.actor.deployment {
+      /myrouter5 {
+        router = broadcast
+        nr-of-instances = 5
+      }
+    }
+    //#config-broadcast
+
+    //#config-scatter-gather
+    akka.actor.deployment {
+      /myrouter6 {
+        router = scatter-gather
+        nr-of-instances = 5
+        within = 10 seconds
+      }
+    }
+    //#config-scatter-gather
+
+    //#config-consistent-hashing
+    akka.actor.deployment {
+      /myrouter7 {
+        router = consistent-hashing
+        nr-of-instances = 5
+        virtual-nodes-factor = 10
+      }
+    }
+    //#config-consistent-hashing
+
+    """)
+
+  case class Message(nbr: Int) extends ConsistentHashable {
+    override def consistentHashKey = nbr
+  }
+
+  class ExampleActor extends Actor with ActorLogging {
+    def receive = {
+      case Message(nbr) ⇒
+        log.debug("Received %s in router %s".format(nbr, self.path.name))
+        sender ! nbr
+    }
+  }
+
+}
+
+class RouterWithConfigDocSpec extends AkkaSpec(RouterWithConfigDocSpec.config) with ImplicitSender {
+
+  import RouterWithConfigDocSpec._
+
+  "demonstrate configured round-robin router" in {
+    //#configurableRouting
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter1")
+    //#configurableRouting
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+  "demonstrate configured random router" in {
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter3")
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+  "demonstrate configured smallest-mailbox router" in {
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter4")
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+  "demonstrate configured broadcast router" in {
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter5")
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(5 * 10)
+  }
+
+  "demonstrate configured scatter-gather router" in {
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter6")
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+  "demonstrate configured consistent-hashing router" in {
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter7")
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+  "demonstrate configured round-robin router with resizer" in {
+    //#configurableRoutingWithResizer
+    val router = system.actorOf(Props[ExampleActor].withRouter(FromConfig()),
+      "myrouter2")
+    //#configurableRoutingWithResizer
+    1 to 10 foreach { i ⇒ router ! Message(i) }
+    receiveN(10)
+  }
+
+}