Rework hack/ and build/ directories.

* Rewrite a bunch of the hack/ directory with modular reusable bash libraries.
* Have 'build/*' build on 'hack/*'.  The stuff in build now just runs hack/* in a docker container.
* Use a docker data container to enable faster incremental builds.
* Standardize output to _output/{local,dockerized}/bin/OS/ARCH/*.  This regularized placement makes cross compilation work.
* Move travis specific scripts under hack/travis

With new dockerized incremental builds, I can do a no-op `make quick-release` in ~30s.  This is a significant improvement.

hack/lib/init.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# 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.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+# The root of the build/dist directory
+KUBE_ROOT=$(
+  unset CDPATH
+  kube_root=$(dirname "${BASH_SOURCE}")/../..
+  cd "${kube_root}"
+  pwd
+)
+
+KUBE_OUTPUT_SUBPATH="${KUBE_OUTPUT_SUBPATH:-_output/local}"
+KUBE_OUTPUT="${KUBE_ROOT}/${KUBE_OUTPUT_SUBPATH}"
+KUBE_OUTPUT_BINPATH="${KUBE_OUTPUT}/bin"
+
+source "${KUBE_ROOT}/hack/lib/util.sh"
+source "${KUBE_ROOT}/hack/lib/logging.sh"
+
+kube::log::install_errexit
+
+source "${KUBE_ROOT}/hack/lib/version.sh"
+source "${KUBE_ROOT}/hack/lib/golang.sh"
+source "${KUBE_ROOT}/hack/lib/etcd.sh"
+
+KUBE_OUTPUT_HOSTBIN="${KUBE_OUTPUT_BINPATH}/$(kube::golang::host_platform)"