Updated Aws::SNS::Resource model.

The major change here is that Aws::SNS::Subscription no longer
requires a topic ARN to construct. For this reason, Subscription
is no longer a subResource of Topic.
Added support for data retrieval policies to Aws::Glacier.
Added support for user metadata to Aws::ElasticTranscoder::Client.
Corrected the version number in an upgrading note.
Bumped version to v2.0.14