Added helper function for all-SVP-rule

Rule combines all-rule and SVP-rule and is required for syllogism testing; together with https://github.com/opencog/relex/pull/115. @AmeBel, could you review this?
The stuff from SVP-rule will also be in a list.  I think you want
```scheme
(append 
    (list (ForAllLink ... ))
    (SVP-rule ... )
)
```
though I am still curious as to why call SVP-rule here instead of letting SVP call its own rule. :)