Refactor to make the HttpAction objects and servlets independent of Jetty.
An indirect dependency existed for HttpAction on SPARQLServer.
Refactoring is a step towards JENA-201 (Deliver Fuseki as a WAR file).

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1517341 13f79535-47bb-0310-9956-ffa450edef68