Make runtime less global for Codec

* Make Codec separate from Scheme
* Move EncodeOrDie off Scheme to take a Codec
* Make Copy work without a Codec
* Create a "latest" package that imports all versions and
  sets global defaults for "most recent encoding"
  * v1beta1 is the current "latest", v1beta2 exists
  * Kill DefaultCodec, replace it with "latest.Codec"
  * This updates the client and etcd to store the latest known version
* EmbeddedObject is per schema and per package now
* Move runtime.DefaultScheme to api.Scheme
* Split out WatchEvent since it's not an API object today, treat it
like a special object in api
* Kill DefaultResourceVersioner, instead place it on "latest" (as the
  package that understands all packages)
* Move objDiff to runtime.ObjectDiff

pkg/api/conversion.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 api
+
+import (
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+)
+
+// Codec is the identity codec for this package - it can only convert itself
+// to itself.
+var Codec = runtime.CodecFor(Scheme, "")
+
+// EmbeddedObject implements a Codec specific version of an
+// embedded object.
+type EmbeddedObject struct {
+	runtime.Object
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (a *EmbeddedObject) UnmarshalJSON(b []byte) error {
+	obj, err := runtime.CodecUnmarshalJSON(Codec, b)
+	a.Object = obj
+	return err
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (a EmbeddedObject) MarshalJSON() ([]byte, error) {
+	return runtime.CodecMarshalJSON(Codec, a.Object)
+}
+
+// SetYAML implements the yaml.Setter interface.
+func (a *EmbeddedObject) SetYAML(tag string, value interface{}) bool {
+	obj, ok := runtime.CodecSetYAML(Codec, tag, value)
+	a.Object = obj
+	return ok
+}
+
+// GetYAML implements the yaml.Getter interface.
+func (a EmbeddedObject) GetYAML() (tag string, value interface{}) {
+	return runtime.CodecGetYAML(Codec, a.Object)
+}