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/util.sh

@@ -0,0 +1,38 @@
+#!/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.
+
+kube::util::sortable_date() {
+  date "+%Y%m%d-%H%M%S"
+}
+
+kube::util::wait_for_url() {
+  local url=$1
+  local prefix=${2:-}
+  local wait=${3:-0.2}
+  local times=${4:-10}
+
+  local i
+  for i in $(seq 1 $times); do
+    local out
+    if out=$(curl -fs $url 2>/dev/null); then
+      kube::log::status ${prefix}${out}
+      return 0
+    fi
+    sleep $wait
+  done
+  kube::log::error "Timed out waiting for ${url}"
+  return 1
+}