Check in the vendor directory

Travis seems to be having issues pulling deps, so we'll have to check in
the vendor directory and prevent the makefile from trying to regenerate
it normally.

vendor/github.com/petar/GoLLRB/llrb/llrb-stats.go

@@ -0,0 +1,46 @@
+// Copyright 2010 Petar Maymounkov. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package llrb
+
+// GetHeight() returns an item in the tree with key @key, and it's height in the tree
+func (t *LLRB) GetHeight(key Item) (result Item, depth int) {
+	return t.getHeight(t.root, key)
+}
+
+func (t *LLRB) getHeight(h *Node, item Item) (Item, int) {
+	if h == nil {
+		return nil, 0
+	}
+	if less(item, h.Item) {
+		result, depth := t.getHeight(h.Left, item)
+		return result, depth + 1
+	}
+	if less(h.Item, item) {
+		result, depth := t.getHeight(h.Right, item)
+		return result, depth + 1
+	}
+	return h.Item, 0
+}
+
+// HeightStats() returns the average and standard deviation of the height
+// of elements in the tree
+func (t *LLRB) HeightStats() (avg, stddev float64) {
+	av := &avgVar{}
+	heightStats(t.root, 0, av)
+	return av.GetAvg(), av.GetStdDev()
+}
+
+func heightStats(h *Node, d int, av *avgVar) {
+	if h == nil {
+		return
+	}
+	av.Add(float64(d))
+	if h.Left != nil {
+		heightStats(h.Left, d+1, av)
+	}
+	if h.Right != nil {
+		heightStats(h.Right, d+1, av)
+	}
+}