hgweb.cgi

This patch make several WSGI related alterations.

First, it changes the server to be almost a generic WSGI server.

Second, it changes request.py to have wsgiapplication and
_wsgirequest.  wsgiapplication is a class that creates _wsgirequests
when called by a WSGI compliant server.  It needs to know whether
or not it should create hgwebdir or hgweb requests.

Lastly, wsgicgi.py is added, and the CGI scripts are altered to
use it to launch wsgiapplications in a WSGI compliant way.

As a side effect, all the keepalive code has been removed from
request.py.  This code needs to be moved so that it is exclusively
in server.py

#!/usr/bin/env python
#
# An example CGI script to use hgweb, edit as necessary

import cgitb, os, sys
cgitb.enable()

# sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
from mercurial.hgweb.hgweb_mod import hgweb
from mercurial.hgweb.request import wsgiapplication
import mercurial.hgweb.wsgicgi as wsgicgi

def make_web_app():
    return hgweb("/path/to/repo", "repository name")

wsgicgi.launch(wsgiapplication(make_web_app))