Simplify the API

I simplify the api by using default parameters. For exemple, if the controller is called `UsersController`, the list can have the name `:users` if nothing else is specified.

There is some points I want to have your opinion before to continue. I introduce two methods in controllers, `smart_listing_resource` and `smart_listing_collection`. I think they can replace options. Instead of do something like `collection: User.something`, the developer can customize the `smart_listing_collection` method.

Now, all `*.js.erb` files are move in the smart_listing view directory. I think we can move the code in partials and place it in the normal file. 

What you think?