add hook_references_dialog_entity_admin_paths_alter()

We need to pass some arguments to our node/add form via the url. I would like to add a the hook_references_dialog_entity_admin_paths_alter() hook to allow this to happen.

This would expose a hook allowing the developer to alter the urls of the various create/edit/add dialog links when entity reference module is being used to create the reference fields.

Patch attached