- Renamed predicates:
  record_term_location ---> record_extra_location,
  declaration_location/4 ---> extra_location/4.

- Added extra_location/4 clause for assertions.
Only showing one pointer to the involved predicate
Removed duplicated clause
Minor bug fix: warnings where not being filtered by module, when reference module was instantiated
Saving Location into assertion_head/7 instead of only the subterm position