add close method to HTTPPool

mwclient/http.py

@@ -188,4 +188,7 @@ class HTTPPool(list):
 	def request(self, method, host, path, headers, data, stream_iter,
 			raise_on_not_ok, auto_redirect):
 		return self.find_connection(host).request(method, host, path,
-			headers, data, stream_iter, raise_on_not_ok, auto_redirect)
+			headers, data, stream_iter, raise_on_not_ok, auto_redirect)
\ No newline at end of file
+	def close(self):
+		for hosts, conn in self:
+			conn.close()
\ No newline at end of file