add multidomainapp example from Anand Chitipothu. Fix issue #99. Thanks!

THANKS

@@ -18,3 +18,4 @@ PA Parent <paparent@paparent.me>
 Travis Cline <travis.cline@gmail.com>
 Adrien Lemaire <lemaire.adrien@gmail.com>
 Oliver Tonnhofer <olt@bogosoft.com>
+Anand Chitipothu <anandology@gmail.com>

examples/multidomainapp.py

@@ -0,0 +1,36 @@
+# -*- coding: utf-8 -
+#
+# This file is part of gunicorn released under the MIT license. 
+# See the NOTICE for more information.
+
+import re
+
+class SubDomainApp:
+    """WSGI application to delegate requests based on domain name.
+"""
+    def __init__(self, mapping):
+        self.mapping = mapping
+
+    def __call__(self, environ, start_response):
+        host = environ.get("HTTP_HOST", "")
+        host = host.split(":")[0] # strip port
+
+        for pattern, app in self.mapping:
+            if re.match("^" + pattern + "$", host):
+                return app(environ, start_response)
+        else:
+            start_response("404 Not Found", [])
+            return [""]
+
+def hello(environ, start_response):
+    start_response("200 OK", [("Content-Type", "text/plain")])
+    return ["Hello, world\n"]
+
+def bye(environ, start_response):
+    start_response("200 OK", [("Content-Type", "text/plain")])
+    return ["Goodbye!\n"]
+
+app = SubDomainApp([
+    ("localhost", hello),
+    (".*", bye)
+])