refactor collectors into subpackage

connector/collector/main.go

@@ -0,0 +1,21 @@
+package collector
+
+import (
+	"math"
+
+	"github.com/bcicen/ctop/logging"
+)
+
+var log = logging.Init()
+
+func round(num float64) int {
+	return int(num + math.Copysign(0.5, num))
+}
+
+// return rounded percentage
+func percent(val float64, total float64) int {
+	if total <= 0 {
+		return 0
+	}
+	return round((val / total) * 100)
+}