Restrict the interface even more.

Restrict the interface to run the worker. (#14)

The worker needs DeleteMessage,ReceiveMessage in order to run.
The worker needs GetQueueUrl only if it is being initialized with a queue name.

Minimal Interface

QueueAPI interface defines the minimum interface

Thanks @bernata!!

Fix an issue with setting WaitTimeSeconds

WaitTimeSeconds was using the config value for MaxNumberOfMessage instead of WaitTimeSecond. This just fixes this issue.

Fixed a problem with the QueueURL

Fix incorrect QueueUrl (#8)

Fix incorrect QueueUrl

Multiple Workers in one app.

Thanks to @vaihtovirta for adding support for multiple workers in a single app.