SendGroup Error Channel Size Fix

Error channel in SendGroup could potentially have up to number of tasks * 2 size. Channel size increased to accomodate for this eventuality.

SendGroup Concurrency Fix

Fixed a bug in SendGroup pooling logic which meant all tasks would be sent synchronously irrespective of the concurrency parameter.

Release v1.0.1

When using AMQP as backend, x-expires parameter is set when declaring a queue in order to set/update task state. This ensures task state queues will eventually get cleanup up.

Initial Release

After almost two years of development, many contributions, improvements and bug fixes it is time for the first official release. I'd like to thank all contributors for their work in shaping this project and making it more robust and production ready.