Expose TDB query engine creation to subclasses.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1513115 13f79535-47bb-0310-9956-ffa450edef68
Test for --parallel in sort(1) and set if present.

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1513116 13f79535-47bb-0310-9956-ffa450edef68