Added EC2::Instance#wait_until_terminated method.
Added `:compute_parts` option to Aws::S3::MultipartUpload#complete.
Added ObjectVersion resources.
Added #clear!` and `#delete!` to `Aws::S3::Bucket`.
Added changelog entry for new S3 features.
Cleaned up ordering in sidebar for API reference.
Fixed HTML formatter for release notes to preserve code blocks.