Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/pkg_resources/tests/test_markers.py

@@ -0,0 +1,8 @@
+import mock
+
+from pkg_resources import evaluate_marker
+
+
+@mock.patch('platform.python_version', return_value='2.7.10')
+def test_ordering(python_version_mock):
+    assert evaluate_marker("python_full_version > '2.7.3'") is True