huge commit regarding the grafite_status:

huge commit regarding the grafite_status:
- in the ng_status component it embeds the lexicon status
- the lexicon status is not passed around alone anymore
- coercions/hints for the ng system are no longer imperative
  (are in the e (for external) status of the tac_status
- ng_refiner does not take in input a look_for_coercions function
  but an aggregate type "rdb" comprising hints and coercions
  (and empty one is passed to disable hints/coercions)
functionalities losses:
- old (generated) hint are no longer translated on the fly
- old coercions are translated in a best effort way
  (no universes calculation)