SPARQLStore / QE / Count query results

Count query results are returned as an integer which makes it impossible to
return a proper object or for that matter possible errors

- Add `SMWQueryResult::setCountValue`, `SMWQueryResult::getCountValue`
- `SMWQueryProcessor` is modified in away that it detects an integer or object
and acts accordingly
Merge pull request #382 from SemanticMediaWiki/sparql-qe-count-result

SPARQLStore / QE / Count query results