Added cache options and Testing against Versions

* Cache options can be passed down to cache implementation
* Simplified api names of model fetch
* Fixed spacing
* Added advanced usage to readme
* Testing Against Rails 3.2 and 4.0
* Added friendly id for better testing against slug lookups
* Appraisals for different gemfile checking
* removing platform testing for now until added to Appraisals
* ugly rails4 check as a new class method