Fix Concurrent modification error

app/src/main/java/fm/touhou/touhoufm/client/MediaBrowserAdapter.kt

@@ -45,10 +45,8 @@ import android.support.v4.media.session.MediaControllerCompat
 import android.support.v4.media.session.MediaSessionCompat
 import android.support.v4.media.session.PlaybackStateCompat
 import android.util.Log
-
 import fm.touhou.touhoufm.service.MusicService
-
-import java.util.ArrayList
+import java.util.*
 
 /**
  * Adapter for a MediaBrowser that handles connecting, disconnecting,
@@ -132,11 +130,12 @@ class MediaBrowserAdapter(private val mContext: Context) {
     }
 
     private fun performOnAllListeners(command: ListenerCommand) {
-        for (listener in mListeners) {
+        val it = mListeners.listIterator()
+        while(it.hasNext()) {
             try {
-                command.perform(listener)
+                command.perform(it.next())
             } catch (e: Exception) {
-                removeListener(listener)
+                it.remove()
             }
         }
     }