Flake8, Semver, Pre-commit

* Added pre-commit: http://pre-commit.com
* Fixed flake8 errors
* Added flake8 pre-commit hooks
* Added pre-commit to Makefile
* Changed VERSION numbering
* Changed versioning to match PEP-0440

tests/test_extensions.py

@@ -44,6 +44,7 @@ class ExtensionsTest(TestCase):
         assert name == 'TestPip'
         assert module
         import noop
+        dir(noop)
 
     def test_installing(self):
         """ Enabling a plugin """