Added support for EC2 CopySnapshot of encrypted volumes.

This adds support for the EC2 2014-05-01 API version.
The `AWS::EC2::Client#copy_snapshot` method will automatically
populated the `:destiation_region` and `:presigned_url` params
for the user to enable copy snapshot on encrypted volumes.
Added support for tags to AWS::ElasticBeanstalk::Client.
Added support to AWS::OpsWork for working with RDS.
Fixed an issue where the configure http_read_timeout was not being observed.

Fixes #544