refactor cpu gauge into standalone widget

widgets/util.go

@@ -0,0 +1,26 @@
+package widgets
+
+import (
+	ui "github.com/gizak/termui"
+)
+
+func mkGauge() *ui.Gauge {
+	g := ui.NewGauge()
+	g.Height = 1
+	g.Border = false
+	g.Percent = 0
+	g.PaddingBottom = 0
+	g.BarColor = ui.ColorGreen
+	g.Label = "-"
+	return g
+}
+
+func colorScale(n int) ui.Attribute {
+	if n > 70 {
+		return ui.ColorRed
+	}
+	if n > 30 {
+		return ui.ColorYellow
+	}
+	return ui.ColorGreen
+}