Add a record with 2 fields : tnode and tattr

The new parameter is -eva-cache-size.

Also take a Hptmap_sig.cache_type argument instead of ~name and ~temporary.
This is consistent with all other cached functions in hptmap.

The warning messages for missing assigns and missing from now have a
category that is set to `error` by default. Moreover, the message is
expanded to note that `assigns \nothing` and `assigns \from \nothing` is
assumed instead and that the analysis is probably incorrect.

... to assigns:invalid-location