Remove unused code (#797)

* delete empty code files

* delete outdated readme

* delete unused code

* dedup license

server/router/middleware/session/repo_test.go

@@ -1,22 +0,0 @@
-// Copyright 2018 Drone.IO Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package session
-
-import (
-	"testing"
-)
-
-func TestSetPerm(t *testing.T) {
-}