Allow controller filters specified to be run

I have a project where I use Authlogic for authentication, and the Authlogic Session information needs to be loaded in a before_filter method for the Base Controller, otherwise it raises an Authlogic::Session::Activation::NotActivatedError error.

I've updated the base controller in Ahoy to allow filters specified by the `filters_to_allow` method to be run, so that I can override the Ahoy::BaseController in my application and then specify a method to be run and add the method name into my defined `filters_to_allow` method.