Router tweaks (#2031)

* Add trailing slash when defined and strict_slashes

* Add partial matching, and fix some issues with url_for

* Cover additional edge cases

* cleanup tests

tests/test_request_stream.py

@@ -646,7 +646,6 @@ def test_streaming_echo():
                 data = await reader.read(4096)
                 assert data
                 buffer += data
-                print(res)
             assert buffer[size : size + 2] == b"\r\n"
             ret, buffer = buffer[:size], buffer[size + 2 :]
             return ret