Add some hacks to support pure HTTPS for WebAdvisor XSS automatic registration hack.

Instead of using a JSONP callback and PHP sessions to store the
TOKENIDX, the XSS script now just updates the URL parameter for the
WebAdvisor login page so that the TOKENIDX will be transferred to
webadvisor.php by a GET variable right when it is needed instead of
asynchronously.

A separate hack to help support HTTPS is that automatic uploading of
assets to Amazon S3 (which has HTTPS access) allows the XSS script to
be served over HTTPS. This eliminates the browser warnings about
accessing mixed secure/insecure content and, thus, hopefully supports
browsers which automatically block insecure content on secure pages.

Add support for manually specifying the base_uri.

This is necessary for me to continue developing on my messed up mpm_peruser
installation of slate_permutate since my apache's idea of its hostname is
wrong.