Add www to test google config

This makes it work right for google.com sub pages when testing via a browser.
Escape string literal when building URL patterns

We can't just mash a string into a regex because sometimes characters in those strings will cause problems
Tell requests not to follow redirects

Before this change, djproxy would follow all redirects and proxy the content that was redirected to instead of passing the redirect on to the downstream consumer.
Generate routes configs should have leading slashes
Disable append_slash in test config

This interferes with the ability to test proxying downstream redirects
Add leading slashes to the generate_routes example
Add support for reversing location headers

Now that djproxy is correctly handling redirects (passing them downstream to the requestor), it needs functionality similar to Apache's ProxyPassReverse directive. This adds that functionality as an additional configuration variable on HttpProxy subclasses.
Add notes about cookie and cookie path manipulation
Add reverse_urls documentation
Configure for coveralls
Add latest release and version butons
Merge pull request #4 from thomasw/pre_release_cleanup

Fix redirect handling and add reverse_urls support