Added port to Request with matcher and test

vcr/request.py

@@ -19,6 +19,10 @@ class Request(object):
     def host(self):
         return urlparse(self.uri).hostname
 
+    @property
+    def port(self):
+        return urlparse(self.uri).port
+
     @property
     def url(self):
         return self.uri