Camel listener for image derivative events

[dannylamb]

Ticket to track progress on the Alpaca end of derivative generation.

I'm creating a small camel listener that will

1. Read from a queue
2. Parse the event for info including image magick options and the source and destination binaries.
3. Issue a request to Houdini's convert service
4. Place the results in drupal at the specified location (create if it does not exist)