Start new tests

run_tests will collect and run the tests on python 2.6+ (need to test 2.5)
without nose.

flake8/tests/test_engine.py

@@ -0,0 +1,8 @@
+from flake8 import engine
+import unittest
+
+
+class TestEngine(unittest.TestCase):
+    def test_get_style_guide(self):
+        g = engine.get_style_guide()
+        self.assertTrue(isinstance(g, engine.StyleGuide))