Test launch script updated to run new tests as well.

At the moment tests requre samples/data copied to source location from master branch.

(cherry picked from commit 56f17e49)

urllib2 raises an exception if an HTTP request produces an error code,
making the test fail earlier.

Add Python 3 support to the Python test.py script.

The print function is used in place of the print statement.

The urlopen function has been moved to urllib.request in Python 3, so
attempt to import it from either location.

TestCase.assert_() has been deprecated in place of
TestCase.assertTrue().

The tests all pass in both Python 2 and 3.