PlayerErrorErrorCode Property

When this switches to using media::Status instead of PipelineStatus we can remove "errorCode" and replace it with the fields from a Status instance. This also seems like a duplicate of the error level enum - there is a todo bug to have that level removed and use this instead. (crbug.com/1068454)

public string ErrorCode { get; set; }

public:
property String^ ErrorCode {
	String^ get ();
	void set (String^ value);
}