Add Support for New KCL Features

[pfifer]

Creating this to track an issue from amazon-kinesis-client Add support for newer KCL features including ApproximateArrivalTimestamp.

Created from awslabs/amazon-kinesis-client#85

[pfifer]

Additional request for awslabs/amazon-kinesis-client#77

• UserRecord's fields are missing. for example 'subSequenceNumber'
• The ability to specify the subsequence number at which to checkpoint
• Additional features

[zdjohn]

re: awslabs/amazon-kinesis-client#77 I correct me if i am wrong. that will requires change on the AWSSDK C# Lib instead of here.