Flex menus2

Removed all view changes to the pages engine, and created a new interface only for Page Menus.

Added rails rendering of page menu links. This is not yet a optimal solutions, as menu links now will be rendered both in rails (initially) and in js (when adding new links).

Also removed the now deprecated refinery_page_id from PagePosition and refactored the code a bit.

These changes are not complete yet.