Updated QueryAsync<T> to expose and accept nextRecordUrl to enabling query result sets greater than 2000 records

The current QueryAsync can only retrieve up to 2000 records because it does not expose or accept nextRecordUrl values. I made minor updates to enable exposing nextRecordUrl and passing it back into QueryAsync to complete a large result set request.

The additions to the SimpleConsole project demonstrate the change and also show how to hit a sandbox environment.