Feature: use version 1.0.0 of the seatgeek/djjob module

The seatgeek/djjob was required as dev-master. This causes an error if you have
your composer's 'minimal-stability' setting configured to 'stable'

The seatgeek/djjob module has a tagged release. We simply require this version
and all is well.

https://github.com/seatgeek/djjob/releases

composer.json

@@ -6,7 +6,7 @@
  "description": "JobQueue for Magento using DJJob",
  "require": {
  "php": ">=5.1",
- "seatgeek/djjob": "dev-master"
+ "seatgeek/djjob": "1.0.0"
  },
  "authors": [
  {