Partial solution for 10.1. We've got grouping, but still need sorting and some printing cleanup.

2018/internal/day10/debug.go

@@ -0,0 +1,15 @@
+package day10
+
+import (
+	"fmt"
+)
+
+func (p *Point) DebugPrintPoint() {
+	fmt.Printf("p=<%d, %d>, v=<%d, %d>\n", p.X, p.Y, p.Xv, p.Yv)
+}
+
+func DebugPrintPoints(points []*Point) {
+	for _, point := range points {
+		point.DebugPrintPoint()
+	}
+}