Pseudo commands, bug fix and more document and sample code (May 25, 2020)

• Introduce pseudo commands: get_query_id, get_query_id_status, stop_query_id, get_driver_version (doc: https://github.com/uber/athenadriver#pseudo-commands, Sample code: https://github.com/uber/athenadriver/tree/master/examples)
• Enable AWS profile manual setup for authentication (Sample code: https://github.com/uber/athenadriver/blob/master/examples/auth.go)
• Query Athena with athenadriver in AWS Lambda (https://github.com/uber/athenadriver/tree/master/examples/lambda/Go)
• One bug fix (8618706)