release v0.3.0 (2015-08-29)

• Revert "Gemfile: kitchen-docker ~> 2.3" (fixes _Kitchen::ActionFailed: Failed to complete #create action: undefined method create' for Tempfile:Class]_, see [kitchen-docker` issue #148).
• .travis.yml: use rvm 2.0.0 for Ruby version 2.0.
• README: Add a link to the netstat cookbook.