etcdmain, embed: export Config and StartEtcd into embed/

Lets programs embed etcd.

Fixes #5430

embed/doc.go

@@ -0,0 +1,37 @@
+// Copyright 2016 The etcd Authors
+//
+// 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 embed provides bindings for embedding an etcd server in a program.
+
+Launch an embedded etcd server using the configuration defaults:
+
+	import (
+		"log"
+
+		"github.com/coreos/etcd/embed"
+	)
+
+	func main() {
+		cfg := embed.NewConfig()
+		cfg.Dir = "default.etcd"
+		e, err := embed.StartEtcd(cfg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer e.Close()
+		log.Fatal(<-e.Err())
+	}
+*/
+package embed