add vendoring with go dep

vendor/github.com/influxdata/influxdb/influxql/linear.go

@@ -0,0 +1,21 @@
+package influxql
+
+// linearFloat computes the the slope of the line between the points (previousTime, previousValue) and (nextTime, nextValue)
+// and returns the value of the point on the line with time windowTime
+// y = mx + b
+func linearFloat(windowTime, previousTime, nextTime int64, previousValue, nextValue float64) float64 {
+	m := (nextValue - previousValue) / float64(nextTime-previousTime) // the slope of the line
+	x := float64(windowTime - previousTime)                           // how far into the interval we are
+	b := previousValue
+	return m*x + b
+}
+
+// linearInteger computes the the slope of the line between the points (previousTime, previousValue) and (nextTime, nextValue)
+// and returns the value of the point on the line with time windowTime
+// y = mx + b
+func linearInteger(windowTime, previousTime, nextTime int64, previousValue, nextValue int64) int64 {
+	m := float64(nextValue-previousValue) / float64(nextTime-previousTime) // the slope of the line
+	x := float64(windowTime - previousTime)                                // how far into the interval we are
+	b := float64(previousValue)
+	return int64(m*x + b)
+}