pkg_resources: Implement resource_stream().

This module is not part of CPython stdlib, but rather of setuptools. But
so happens that it's functionality either lies on critical path, or should
be duplicated, in pkgutil module.

pkg_resources/pkg_resources.py

@@ -0,0 +1,9 @@
+import os
+import os.path
+
+def resource_stream(package, resource):
+    p = __import__(package)
+    d = os.path.dirname(p.__file__)
+    if d[0] != "/":
+        d = os.getcwd() + "/" + d
+    return open(d + "/" + resource, "rb")