Add test driver class

[namedgraph]

It should be possible to run tests from command line, using the following arguments:

• dataset URI or SPARQL endpoint
• sitemap ontology URI
• request URI
• request headers

The driver class would need to implement main() method. It could be used to run scripts from a suite that tests the processor's conformance to the specification.

[namedgraph]

This seems to be Jena's cmd class:
https://github.com/apache/jena/blob/master/jena-base/src/main/java/jena/cmd/CmdMain.java

[namedgraph]

The tests suite could be similar to the one of SPARQL:
http://www.w3.org/2001/sw/DataAccess/tests/r2
http://www.w3.org/2009/sparql/docs/tests/
http://www.w3.org/2009/sparql/docs/tests/summary.html