adding equative type sentences 

@ruiting @AmeBel @linas  please have a look on binary relationships.
If you want to keep consistence with the normal comparative representations, it should be like:

```
_compare(intelligent, Jack)
_than(Jack, Ben)
degree(intelligent, equal)
```

but I guess this is too deep for RelEx...  So I think we can just "as(intelligent, Jack)", without underscore in front of "as", because "as" appears in the sentence.