Updating to Dropwizard stable version 0.7.0 and extra documentation

I've made the following changes:

* Upgraded Dropwizard version to 0.7.0
* Changed the dropwizard-jobs project version to be pegged against dropwizard project version. I.e. 0.7.0.1, 0.7.0.2 etc. This is done similar to dropwizard-guice project.
* Updated README.md to add in specific usage instructions for Guice jobs.