Add public initializer with queue and change default queue label

Author: ChaosCoder

Sources/Shouter/Shouter.swift

@@ -14,7 +14,11 @@ public class Shouter {
 
     fileprivate typealias Key = String
     fileprivate var observers: [Key: NSHashTable<AnyObject>] = [:]
-    fileprivate let notificationQueue = DispatchQueue(label: "com.swift.notification.center.dispatch.queue", attributes: .concurrent)
+    fileprivate let notificationQueue: DispatchQueue
+    
+    public init(notificationQueue: DispatchQueue = DispatchQueue(label: "de.chaosspace.Shouter.dispatch.queue", attributes: .concurrent)) {
+        self.notificationQueue = notificationQueue
+    }
 
     public func register<T>(_ type: T.Type, observer: T) {
         notificationQueue.sync(flags: .barrier) {