add examples/httpserver.py

examples/httpserver.py

+"""HTTP server listening on port 8800.
+
+Uses libevent API directly and thus may be dangerous.
+WSGI interface is probably a safer choice, see examples/wsgiserver.py.
+"""
+from gevent import http
+
+def callback(r):
+    if r.uri == '/':
+        r.add_output_header('Content-Type', 'text/html')
+        r.send_reply(200, "OK", '<b>hello world</b>')
+    else:
+        r.add_output_header('Content-Type', 'text/html')
+        r.send_reply(404, "Not Found", "<h1>Not Found</h1>")
+
+print __doc__
+http.HTTPServer(callback).serve_forever(('0.0.0.0', 8800))