Channel Cancel checks for Channeled AOE DPS Spells

Hello everyone,

I liked the channel cancel I did on mage recently, where they cancel blizzard if there is only 1 enemy left. I decided to do the same for the following classes:

Druid: Hurricane
Hunter: Volley
Priest: Mind Sear
Warlock: Rain of Fire

I moved the "ChannelCancel" action to it's own file, so other classes could benefit from it. I removed it from the mageactions.

src/strategy/actions/CancelChannelAction.cpp

@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2016+ AzerothCore <www.azerothcore.org>, released under GNU GPL v2 license, you may redistribute it
+ * and/or modify it under version 2 of the License, or (at your option), any later version.
+ */
+
+#include "CancelChannelAction.h"
+#include "Player.h"
+#include "PlayerbotAI.h"
+
+bool CancelChannelAction::Execute(Event event)
+{
+    if (bot->GetCurrentSpell(CURRENT_CHANNELED_SPELL))
+    {
+        bot->InterruptSpell(CURRENT_CHANNELED_SPELL);
+        return true;
+    }
+    return false;
+}