add options to respond_with_bip

hi, i added an optional options hash to respond_with_bip. Our app uses STI models and share a view that uses best_in_place and share a controller. The view uses :object_name and :path options to configure it, but the controller extensions dont have corresponding options. (I know its a bit unusual to share a resource controller for STI models but thats how our app does it in this case). Thanks!

example: 

    respond_with_bip post, class_name: 'Post', param_key: 'post'