init expanded view, add cpu histogram

widgets/hist.go

@@ -0,0 +1,22 @@
+package widgets
+
+type HistData struct {
+	data    []int
+	labels  []string
+	maxSize int
+}
+
+func NewHistData(max int) HistData {
+	return HistData{
+		data:    make([]int, max),
+		labels:  make([]string, max),
+		maxSize: max,
+	}
+}
+
+func (h HistData) Append(val int) {
+	if len(h.data) >= h.maxSize {
+		h.data = append(h.data[:0], h.data[1:]...)
+	}
+	h.data = append(h.data, val)
+}