Move doc hosting to readthedocs.org
Document links to project resources
Hide old releases from table of contents
Add examples of SQS and SNS autoscaling data.

There's a sample of a plain ol' SQS message, an SQS message sent by
EC2 during an autoscaling *launch* event, and then the associated RSA
certificate (a.k.a. public key) used to verify the signature of the
launch event message.
Add notes about dispatcher feature