Changed/fixed the way Django handles SCRIPT_NAME and PATH_INFO (or

equivalents). Basically, URL resolving will only use the PATH_INFO and the
SCRIPT_NAME will be prepended by reverse() automatically. Allows for more
portable development and installation. Also exposes SCRIPT_NAME in the
HttpRequest instance.

There are a number of cases where things don't work completely transparently,
so mod_python and fastcgi users should read the relevant docs.

Fixed #285, #1516, #3414.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8015 bcc190cf-cafb-0310-a4f2-bffc1f526a37