remove Grid struct, move cursor into own package file

main.go

@@ -5,11 +5,18 @@ import (
 	"os"
 
 	"github.com/bcicen/ctop/config"
+	"github.com/bcicen/ctop/cwidgets/compact"
 	"github.com/bcicen/ctop/logging"
+	"github.com/bcicen/ctop/widgets"
 	ui "github.com/gizak/termui"
 )
 
-var log *logging.CTopLogger
+var (
+	log    *logging.CTopLogger
+	cursor *GridCursor
+	cGrid  = compact.NewCompactGrid()
+	header = widgets.NewCTopHeader()
+)
 
 func main() {
 	defer func() {
@@ -19,19 +26,20 @@ func main() {
 			os.Exit(1)
 		}
 	}()
+
 	config.Init()
 	log = logging.Init()
 	if config.GetSwitchVal("loggingEnabled") {
 		logging.StartServer()
 	}
+	cursor = NewGridCursor()
 	if err := ui.Init(); err != nil {
 		panic(err)
 	}
 	defer ui.Close()
 
-	g := NewGrid()
 	for {
-		exit := Display(g)
+		exit := Display()
 		if exit {
 			log.Notice("shutting down")
 			log.Exit()