cursor cannot be set, error message is displayed directly when an exception occurs

[danielhuang-030]

Hi, I found two issues when used:

1. cursor cannot be set
   Because "string" == 0 will always returns true in PHP.
   

   laravel-cloudsearch/src/Query/StructuredQueryBuilder.php

   Line 142 in 5556db9

   $this->cursor = $cursor == 0 ? 'initial' : $cursor;

   
   After setting $cursor will only be "initial".

2. error message is displayed directly when an exception occurs
   

   laravel-cloudsearch/src/CloudSearcher.php

   Line 194 in 5556db9

   dd($e->getAwsErrorMessage() ?: $e->getMessage());

Please help confirm, thanks.