Add test capturing possible violation in expectation due to new Python 2.7.10 release. Ref #380.

pkg_resources/tests/test_markers.py

+try:
+	import unittest.mock as mock
+except ImportError:
+	import mock
+
+from pkg_resources import evaluate_marker
+
+
+@mock.patch.dict('pkg_resources.MarkerEvaluation.values',
+	python_full_version=mock.Mock(return_value='2.7.10'))
+def test_lexicographic_ordering():
+	"""
+	Although one might like 2.7.10 to be greater than 2.7.3,
+	the marker spec only supports lexicographic ordering.
+	"""
+	assert evaluate_marker("python_full_version > '2.7.3'") is False