JENA-537
Provide a default query syntax, and apply it to a command line string argument.
Syntax determination is:
     *  Explicitly given --syntax</li>
     *  File extension
     *  Command default
     *  System default

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1525334 13f79535-47bb-0310-9956-ffa450edef68