adding more laravel infrastructure and installation docs

I reorganized the classes a bit (sorry) and verified that the Repository tests still pass. The other changes are related to the efforts to make the package installation seamless. 

The short of the installation strategy is that the ServiceProvider replaces the IoC key `cache` with a GracefulCache version of the CacheManager, that extends the stock Laravel CacheManager. This child class overrides the `repository()` method to return an instance of the GracefulCache Repository instead of the stock Laravel Repository.

This implementation plan should extend this packages effectiveness to all drivers. The previous implementation plan requires that each driver be explicitly declared and return the GracefulCache Repository manually.

Fair warning, I am not sure if the timing of the providers is accurate, but I would give it a shot in your test environment and see how it performs. Let me know if there are other issues!