Update opsworks-agent, implement build script for Ubuntu 14.04 LTS

* update opsworks-agent to release 316
* utilize native install script and stub config files expected by some of the built-in opsworks-cookbooks (e.g.deploy)
* update vagrant box commands to remove depreciated use
* add build process for Ubuntu 14.04 LTS alongside 12.04.4 LTS and make it the default