Backport source links from 3.x.

Existing links have been updated to use the new reST role.  In some
files, I have also made cosmetic changes to the header.
diff --git a/Doc/library/urlparse.rst b/Doc/library/urlparse.rst
index 88dafa9..f118845 100644
--- a/Doc/library/urlparse.rst
+++ b/Doc/library/urlparse.rst
@@ -17,6 +17,9 @@
    The :term:`2to3` tool will automatically adapt imports when converting
    your sources to 3.0.
 
+**Source code:** :source:`Lib/urlparse.py`
+
+--------------
 
 This module defines a standard interface to break Uniform Resource Locator (URL)
 strings up in components (addressing scheme, network location, path etc.), to
@@ -33,11 +36,6 @@
 .. versionadded:: 2.5
    Support for the ``sftp`` and ``sips`` schemes.
 
-.. seealso::
-
-   Latest version of the `urlparse module Python source code
-   <http://svn.python.org/view/python/branches/release27-maint/Lib/urlparse.py?view=markup>`_
-
 The :mod:`urlparse` module defines the following functions: