Resolve "calculate_mean fails for Python 2"

CHANGELOG.rst

@@ -2,6 +2,7 @@ Unreleased changes
 ------------------
 
 * A bugfix 
+* Fixed a bug in calculate_mean which was present in python 2.7 envoronments
 
 
 Version 0

foo/bar.py

 #!usr/bin/env python
 # -*- coding: utf-8 -*-
 # Filename: bar.py
+from __future__ import division
 """
 The bar module.
 
 """
 
-__author__ = "Your Name"
+__author__ = "Jürgen"
 __credits__ = ["The guy in your office", "Tom"]
 __license__ = "MIT"
 __maintainer__ = "Your Buddy"

foo/tests/test_bar.py

@@ -8,7 +8,7 @@ from foo.bar import whats_the_meaning_of_life, calculate_mean
 __author__ = "Your Name"
 __credits__ = []
 __license__ = "MIT"
-__maintainer__ = "Your Name"
+__maintainer__ = "Jürgen"
 __email__ = "yname@km3net.de"
 
 
@@ -38,3 +38,6 @@ class TestCalculateMean(TestCase):
 
     def test_calculate_mean_returns_correct_value_for_negative_numbers(self):
         assert -3 == calculate_mean([-1, -2, -3, -4, -5])
+
+    def test_calculate_mean_of_some_other_numbers(self):
+        self.assertAlmostEqual(2.5, calculate_mean([1, 2, 3, 4]))