Temporarily add go-agentx (w/ fixes to lexico ordering)

go-agentx/list_item.go

@@ -0,0 +1,13 @@
+// Copyright 2018 The agentx authors
+// Licensed under the LGPLv3 with static-linking exception.
+// See LICENCE file for details.
+
+package agentx
+
+import "github.com/posteo/go-agentx/pdu"
+
+// ListItem defines an item of the list handler.
+type ListItem struct {
+	Type  pdu.VariableType
+	Value interface{}
+}