funnel wake-on-lan start through host, not direct

The network card's wake-on-lan previously was sending a computer.start
message directly to the machine. But some hosts, specifically the Drone
need to make certain start actions before the machine starts. For
instance, the drone zeros its velocity (technically, it rises by .5m)

closes #2866

src/main/scala/li/cil/oc/common/entity/Drone.scala

@@ -164,7 +164,13 @@ class Drone(val world: World) extends Entity(world) with MachineHost with intern
 
   override def isPaused = machine.isPaused
 
-  override def start() = machine.start()
+  override def start(): Boolean = {
+    if (world.isRemote || machine.isRunning) {
+      return false
+    }
+    preparePowerUp()
+    machine.start()
+  }
 
   override def pause(seconds: Double) = machine.pause(seconds)
 
@@ -474,7 +480,6 @@ class Drone(val world: World) extends Entity(world) with MachineHost with intern
         }
       }
       else if (!world.isRemote && !machine.isRunning) {
-        preparePowerUp()
         start()
       }
     }

src/main/scala/li/cil/oc/server/component/NetworkCard.scala

@@ -176,16 +176,18 @@ class NetworkCard(val host: EnvironmentHost) extends prefab.ManagedEnvironment w
       }
       // Accept wake-up messages regardless of port because we close all ports
       // when our computer shuts down.
-      packet.data match {
-        case Array(message: Array[Byte]) if wakeMessage.contains(new String(message, Charsets.UTF_8)) =>
-          node.sendToNeighbors("computer.start")
-        case Array(message: String) if wakeMessage.contains(message) =>
-          node.sendToNeighbors("computer.start")
-        case Array(message: Array[Byte], _*) if wakeMessageFuzzy && wakeMessage.contains(new String(message, Charsets.UTF_8)) =>
-          node.sendToNeighbors("computer.start")
-        case Array(message: String, _*) if wakeMessageFuzzy && wakeMessage.contains(message) =>
-          node.sendToNeighbors("computer.start")
-        case _ =>
+      val wakeup: Boolean = packet.data match {
+        case Array(message: Array[Byte]) if wakeMessage.contains(new String(message, Charsets.UTF_8)) => true
+        case Array(message: String) if wakeMessage.contains(message) => true
+        case Array(message: Array[Byte], _*) if wakeMessageFuzzy && wakeMessage.contains(new String(message, Charsets.UTF_8)) => true
+        case Array(message: String, _*) if wakeMessageFuzzy && wakeMessage.contains(message) => true
+        case _ => false
+      }
+      if (wakeup) {
+        host match {
+          case ctx: Context => ctx.start()
+          case _ => node.sendToNeighbors("computer.start")
+        }
       }
     }
   }