Fix null exception when detectorResult.Bits has no value
Fix null exception when detectorResult.Bits has no value

DHMechatronicAG/ZXing.Net,DHMechatronicAG/ZXing.Net,DHMechatronicAG/ZXing.Net,micjahn/ZXing.Net,micjahn/ZXing.Net,micjahn/ZXing.Net