Move scheduler code out of plugin directory.

This moves plugin/pkg/scheduler to pkg/scheduler and
plugin/cmd/kube-scheduler to cmd/kube-scheduler.

Bulk of the work was done with gomvpkg, except for kube-scheduler main
package.

pkg/scheduler/algorithm/priorities/least_requested.go

@@ -0,0 +1,53 @@
+/*
+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.
+*/
+
+package priorities
+
+import (
+	schedulerapi "k8s.io/kubernetes/pkg/scheduler/api"
+	"k8s.io/kubernetes/pkg/scheduler/schedulercache"
+)
+
+var (
+	leastResourcePriority = &ResourceAllocationPriority{"LeastResourceAllocation", leastResourceScorer}
+
+	// LeastRequestedPriority is a priority function that favors nodes with fewer requested resources.
+	// It calculates the percentage of memory and CPU requested by pods scheduled on the node, and
+	// prioritizes based on the minimum of the average of the fraction of requested to capacity.
+	//
+	// Details:
+	// cpu((capacity-sum(requested))*10/capacity) + memory((capacity-sum(requested))*10/capacity)/2
+	LeastRequestedPriorityMap = leastResourcePriority.PriorityMap
+)
+
+func leastResourceScorer(requested, allocable *schedulercache.Resource) int64 {
+	return (leastRequestedScore(requested.MilliCPU, allocable.MilliCPU) +
+		leastRequestedScore(requested.Memory, allocable.Memory)) / 2
+}
+
+// The unused capacity is calculated on a scale of 0-10
+// 0 being the lowest priority and 10 being the highest.
+// The more unused resources the higher the score is.
+func leastRequestedScore(requested, capacity int64) int64 {
+	if capacity == 0 {
+		return 0
+	}
+	if requested > capacity {
+		return 0
+	}
+
+	return ((capacity - requested) * int64(schedulerapi.MaxPriority)) / capacity
+}