First steps towards Python 3 compatibility.

Handles the case where the SSOLoginServer URL has a path component.

This makes the C implementation compatible with the Go one, which
generates unpadded base64-encoded tokens.

Since swig generates a .py file, the build_ext step needs to run
before the build one.

This reverts commit 76caf208.

This reverts commit 01eb7558.

This allows for the package to be properly installed by pip
(and a standalone python setup.py install), otherwise the distutils
build stage won't see the swig-generated file.

There are probably better solutions to this issue.

Pull reference code out of apache's own util_cookies.c (which is
unfortunately not part of libapr so we can't link to it in our tests).

Also use libapr for url-escaping, getting rid of some ugly code.

Makes the code a lot easier to read. Now that Debian stable has Apache
2.4, there's really no need to keep the legacy code around (also, it
is probably buggy).

The SSO_LIBS variable was undefined.

The cookie parser wasn't checking for an equal sign after the cookie
name. Add tests for it.

The call to sso_validate in mod_sso_check_user_id wasn't using the
right sso_service variable, causing service autodetection to fail.

We were using the wrong 'service' variable. Added a test to detect
this situation.

The output is now slightly more readable. Set the DUMP_APACHE_LOG
environment variable to 1 to dump the apache2 logs after each test.

Makes it easy for web applications to retrieve the original SSO ticket.

Along with a minor refactoring of the test driver to support a second
Apache test file with a different configuration.