Use file tags to generate deep-copies

This drives most of the logic of deep-copy generation from tags like:
  // +deepcopy-gen=package
..rather than hardcoded lists of packages.  This will make it possible to
subsequently generate code ONLY for packages that need it *right now*, rather
than all of them always.

Also remove pkgs that really do not need deep-copies (no symbols used
anywhere).

pkg/api/unversioned/doc.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2016 The Kubernetes 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.
+*/
+
+// +k8s:deepcopy-gen=generate
+
+package unversioned