Release v2.0.19 - 2015-01-15

References: #191, #193, aws/aws-sdk-ruby#684

• Feature - Aws::ElasticTranscoder - Updated Client to support the new
  encryption features.
• Feature - Waiters - Added support for version 2 of the waiters
  definition format.
• Issue - Pagingation - Resolved an issue where an empty hashes or arrays
  were being treated as valid next tokens for paging response. This appears
  to only have affected Aws::DynamoDB::Client#batch_get_item.
• Issue - Instance Profile Credentials - Resolved an issue where instance
  profile credentials would never load if the first attempt fails.
  See GitHub issue #193.
• Issue - Aws::S3::Object - Resolved an issue with #upload_file where
  options intended for #initiate_multipart_upload are being passed along
  to individual #upload_part API calls. Fixes
  GitHub issue #684.