Make config file configurable via attributes

Expose some basic attributes that can be used to control
proxy address, allowed clients and log level.
Provide some basic metadata

Fix Foodcritic FC045 by setting the name of the cookbook.
Provide some basic platform support metadata.
Add support for Berkshelf

berks init creates these basic files for managing/testing cookbook
with http://berkshelf.com/. Install berkshelf via bundler and then
test the cookbook using Vagrant.

Vagrantfile is customized to use Ubuntu 12.04 provided by Opscode.
Merge branches 'berkshelf' and 'basic-attributes'