* Remove ActionEndpoint in favor of passing a block to MiddlewareStack
* Always create a Request; the performance win of RackDelegation is around
the response; the Request object hit is limited to a single object allocation
* #dispatch takes a Request
add lazy_load_hooks.rb, which allows us to declare code that
should be run at some later time. For instance, this allows
us to defer requiring ActiveRecord::Base at boot time purely
to apply configuration. Instead, we register a hook that should
apply configuration once ActiveRecord::Base is loaded.
With these changes, brings down total boot time of a
new app to 300ms in production and 400ms in dev.
TODO: rename base_hook
