Kubernetes Mesos integration

This commit includes the fundamental components of the Kubernetes Mesos
integration:

* Kubernetes-Mesos scheduler
* Kubernetes-Mesos executor
* Supporting libs

Dependencies and upstream changes are included in a separate commit for easy
review.

After this initial upstream, there'll be two PRs following.

* km (hypercube) and k8sm-controller-manager #9265
* Static pods support #9077

Fixes applied:

- Precise metrics subsystems definitions
  -  mesosphere/kubernetes-mesos#331
  - https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion_r31875232
  - https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion_r31875240
- Improve comments and add clarifications
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875208
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875226
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875227
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875228
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875239
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875243
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875234
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875256
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875255
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875251
- Clarify which Schedule function is actually called
  - Fixes https://github.com/GoogleCloudPlatform/kubernetes/pull/8882#discussion-diff-31875246

contrib/mesos/target.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+# Copyright 2014 The Kubernetes Authors 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.
+
+# The set of server targets that we are only building for Linux
+# Used by hack/lib/golang.sh
+kube::contrib::mesos::server_targets() {
+  local -r targets=(
+    contrib/mesos/cmd/k8sm-scheduler
+    contrib/mesos/cmd/k8sm-executor
+  )
+  echo "${targets[@]}"
+}
+
+# The set of test targets that we are building for all platforms
+# Used by hack/lib/golang.sh
+kube::contrib::mesos::test_targets() {
+  local -r targets=(
+    contrib/mesos/cmd/k8sm-redirfd
+  )
+  echo "${targets[@]}"
+}
+
+# The set of source targets to include in the kube-build image
+# Used by build/common.sh
+kube::contrib::mesos::source_targets() {
+  local -r targets=(
+    contrib/mesos
+  )
+  echo "${targets[@]}"
+}