Grid properties: process the integer grid properties fully before starting with the double ones

this is needed because the initializers of double grid properties
sometimes need the final value of integer properties (like SATNUM,
etc)
EP-scaling initializer: use the integer grid properties instead of the keyword directly

this is required as sometimes these fields are processed and sometimes
the keyword corresponding to the field is not present in the deck:

```
SATNUM
1*1 /

COPY
'SATNUM' 'IMBNUM' /
```

(this deck will have an IMBNUM property but no IMBNUM keyword.)
fixup! grid properties: implement a table-lookup initializer for the endpoint scaling keywords