Add support for Dead Letter Queues to SQS
Merge branch 'sqs-dlq' into develop.

Add support for dead letter queues (DLQ) to SQS.
Readded eu-west-1 for SES.
Merge branch 'develop' of github.com:boto/boto into develop
Added us-west-2 to SES.
Merge branch 'ses-us-west-2' into develop
Merge branch 'develop' of github.com:boto/boto into develop
Version bump to 2.24.0.