* throws non-generic webexception for batch request errors due to different json error message from fb (issue #5887)
* throws non-generic webexception for batch request errors due to different json error message from fb (issue #5887)

facebook-csharp-sdk/facebook-csharp-sdk,simpleverso/facebook-csharp-sdk,simpleverso/facebook-csharp-sdk,swiese/facebook-csharp-sdk,facebook-csharp-sdk/facebook-csharp-sdk,swiese/facebook-csharp-sdk,ladyquartermaine/facebook-csharp-sdk,ladyquartermaine/facebook-csharp-sdk,Ali-Shaltout/facebook-csharp-sdk,Ali-Shaltout/facebook-csharp-sdk