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/avgvar.go

@@ -0,0 +1,39 @@
+// 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
+
+import "math"
+
+// avgVar maintains the average and variance of a stream of numbers
+// in a space-efficient manner.
+type avgVar struct {
+	count      int64
+	sum, sumsq float64
+}
+
+func (av *avgVar) Init() {
+	av.count = 0
+	av.sum = 0.0
+	av.sumsq = 0.0
+}
+
+func (av *avgVar) Add(sample float64) {
+	av.count++
+	av.sum += sample
+	av.sumsq += sample * sample
+}
+
+func (av *avgVar) GetCount() int64 { return av.count }
+
+func (av *avgVar) GetAvg() float64 { return av.sum / float64(av.count) }
+
+func (av *avgVar) GetTotal() float64 { return av.sum }
+
+func (av *avgVar) GetVar() float64 {
+	a := av.GetAvg()
+	return av.sumsq/float64(av.count) - a*a
+}
+
+func (av *avgVar) GetStdDev() float64 { return math.Sqrt(av.GetVar()) }