Replace the --base code with relative paths.

Replace the --base code with relative paths.

Most of the functionality turned out to be overkill since
relative paths work fine, too.  The only broken thing is
lighttpd 1.4 which doesn't support proxying of stuff like
  /darkstat/ -> http://localhost:667/
But this will be fixed properly in mod_proxy_core in 1.5
once (if ever) it is released.