Added clean exec functionality + ACI implementation - V2 (#244)

* Stubs and vkubelet changes

* added dependencies

* Azure provider exec implementation

* added missing dependencies

* added vkubelet imports

* added huawei exec stub

* Fixed exec tab functionality / stdin buffer length

* Removed unused import

* Added provider function GetPodFullName + ACI implementation

* Added error handling in ACI provider exec

vendor/github.com/gorilla/websocket/client_clone.go

@@ -0,0 +1,16 @@
+// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.8
+
+package websocket
+
+import "crypto/tls"
+
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return cfg.Clone()
+}