Refactor asynchronous actions to avoid thread usage

Adds custom coroutines specifically for use within Actions.  This
implements all features of the previous system, however, does not rely
on a separate executor to wake up continuations.

Note: since Actions are still ran by an executor and a small chance of
overlap exists the ActionCoroutine implementation uses atomic counters
and references.

game/plugin/consumables/src/consumables.plugin.kts

@@ -1,3 +1,4 @@
+import org.apollo.game.action.ActionBlock
 import org.apollo.game.action.AsyncAction
 import org.apollo.game.message.impl.ItemOptionMessage
 import org.apollo.game.model.Animation
@@ -27,7 +28,7 @@ class ConsumeAction(val consumable: Consumable, player: Player, val slot: Int) :
         }
     }
 
-    suspend override fun executeActionAsync() {
+    override fun action(): ActionBlock = {
         consumable.consume(mob, slot)
         mob.playAnimation(Animation(CONSUME_ANIMATION_ID))
         wait(consumable.delay)

game/plugin/dummy/src/dummy.plugin.kts

@@ -1,6 +1,7 @@
 import kotlinx.coroutines.experimental.*
 import kotlinx.coroutines.experimental.channels.Channel
 import kotlinx.coroutines.experimental.selects.select
+import org.apollo.game.action.ActionBlock
 import org.apollo.game.action.AsyncDistancedAction
 import org.apollo.game.action.DistancedAction
 import org.apollo.game.message.impl.ObjectActionMessage
@@ -53,9 +54,9 @@ class DummyAction(val player: Player, position: Position) : AsyncDistancedAction
     }
 
 
-    override suspend fun executeActionAsync() {
+    override fun action(): ActionBlock = {
         mob.sendMessage("You hit the dummy.")
-        mob.turnTo(this.position)
+        mob.turnTo(position)
         mob.playAnimation(PUNCH_ANIMATION)
         wait()
 
@@ -66,8 +67,6 @@ class DummyAction(val player: Player, position: Position) : AsyncDistancedAction
         } else {
             skills.addExperience(Skill.ATTACK, EXP_PER_HIT)
         }
-
-        stop()
     }
 
 }

game/plugin/skills/mining/src/mining.plugin.kts

@@ -1,3 +1,4 @@
+import org.apollo.game.action.ActionBlock
 import org.apollo.game.action.AsyncDistancedAction
 import org.apollo.game.action.DistancedAction
 import org.apollo.game.message.impl.ObjectActionMessage
@@ -68,18 +69,15 @@ class MiningAction(player: Player, val tool: Pickaxe, val target: MiningTarget)
         }
     }
 
-    override fun start() {
+    override fun action() : ActionBlock = {
         mob.turnTo(position)
 
         val level = mob.skills.mining.currentLevel
-
         if (level < target.ore.level) {
             mob.sendMessage("You do not have the required level to mine this rock.")
             stop()
         }
-    }
 
-    override suspend fun executeActionAsync() {
         mob.sendMessage("You swing your pick at the rock.")
         mob.playAnimation(tool.animation)
 
@@ -88,14 +86,12 @@ class MiningAction(player: Player, val tool: Pickaxe, val target: MiningTarget)
         val obj = target.getObject(mob.world)
         if (!obj.isPresent) {
             stop()
-            return
         }
 
         if (target.isSuccessful(mob)) {
             if (mob.inventory.freeSlots() == 0) {
                 mob.inventory.forceCapacityExceeded()
                 stop()
-                return
             }
 
             if (mob.inventory.add(target.ore.id)) {
@@ -105,7 +101,6 @@ class MiningAction(player: Player, val tool: Pickaxe, val target: MiningTarget)
                 mob.skills.addExperience(Skill.MINING, target.ore.exp)
                 mob.world.expireObject(obj.get(), target.ore.objects[target.objectId]!!, target.ore.respawn)
                 stop()
-                return
             }
         }
     }
@@ -142,7 +137,7 @@ class ProspectingAction(val m: Player, val p: Position, val ore: Ore) : AsyncDis
         }
     }
 
-    suspend override fun executeActionAsync() {
+    override fun action() : ActionBlock = {
         mob.sendMessage("You examine the rock for ores...")
         mob.turnTo(position)