Changed file name, added contextual inference example

Split into two pull requests: https://github.com/opencog/opencog/pull/765
Would one define this concept in terms of an inheritance from the intersection of two distinct concepts?
```
(InheritanceLink
    (ConceptNode "Non-CanadianPeople")
    (AndLink
        (NotLink
             (ConceptNode "Canadian))
        (ConceptNode "People")))
```