Add all the A tasks

Task/Averages-Mean-angle/Go/averages-mean-angle.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+  "fmt"
+  "math"
+  "math/cmplx"
+)
+
+func deg2rad(d float64) float64 { return d * math.Pi / 180 }
+func rad2deg(r float64) float64 { return r * 180 / math.Pi }
+
+func mean_angle(deg []float64) float64 {
+  sum := 0i
+  for _, x := range deg { sum += cmplx.Rect(1, deg2rad(x)) }
+  return rad2deg(cmplx.Phase(sum))
+}
+
+func main() {
+  for _, angles := range [][]float64 {{350, 10}, {90, 180, 270, 360}, {10, 20, 30}} {
+    fmt.Printf("The mean angle of %v is: %f degrees\n", angles, mean_angle(angles))
+  }
+}