Feature refactor

Part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594

- make directory structure mirror app
- refactor path_to method to go to a path for a role
- implement webkit hook so that users can switch to the webkit driver when needed
- added headless gem so cucumber does not require special invocation at the command line if webkit driver used
- implement database cleaner in cucumber
- add Readme.md to feature directory