[WIP] Avoids having to specify the view folder in render/2

As it stands now you have to specify the relative path to the view in order for it to be rendered. 

This PR adds support to `render :index`, `render "index"` to specify the particular view and takes the controller name to look in what folder, while trying to maintain the backwards compatibility. And will add along the way automatic rendering of a view with the same name as the action.

I'm still trying to figure out how to test the controller and action automatic rendering. And would love to hear opinions, comments and constructive criticism .
Might want to use `Map.get/3` here to prevent the `KeyError`s from happening.