merge with master + fixups

tests/python_tests/datasource_test.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-from nose.tools import eq_
+from nose.tools import eq_, raises
 from utilities import execution_path, run_all
 import os, mapnik
 from itertools import groupby

tests/python_tests/image_test.py

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 
 import os, mapnik
-from nose.tools import eq_,raises
+from nose.tools import eq_,raises, assert_almost_equal
 from utilities import execution_path, run_all, get_unique_colors
 
 def setup():

tests/python_tests/image_tiff_test.py

@@ -3,7 +3,7 @@
 
 import os, mapnik
 import hashlib
-from nose.tools import eq_
+from nose.tools import eq_, assert_not_equal
 from utilities import execution_path, run_all
 
 def hashstr(var):