Elder.js Hook: allRequests

The main use here is to allow users to adjust the requests that Elder.js is aware of.

• This could be used for incremental builds. By filtering and overwriting the allRequests array building just a single route or even a single request is doable.
• This hook is used by elderjs-plugin-random to register temporary requests that it later intercepts to redirect to a random page of a route.
• This hook is used by elderjs-plugin-markdown to register processed markdown files and their slugs Elder.js

NOTE: If you are modifying 'allRequests' you must set 'request.route' key for each request.