Update PlayerConnection.cs

[Xbox One] Adding port that XB1 uses to connection list
    
    * XB1 uses 58997 for multicast.  I believe 57997 was already in the list
      for the XB1, and that might have just been a type-o.  I'm not certain
      about that though, so I left in the list incase anyone else is using it.
Merge pull request #7 from Unity-Technologies/remotes/origin/unity-4.3/xboxone

Update PlayerConnection.cs