move ui.Init() into main, allow any key to exit help dialog

main.go

@@ -1,15 +1,19 @@
 package main
 
 import (
-	"os"
+	ui "github.com/gizak/termui"
 )
 
 func main() {
+	if err := ui.Init(); err != nil {
+		panic(err)
+	}
+	defer ui.Close()
 	g := NewGrid()
 	for {
 		exit := Display(g)
 		if exit {
-			os.Exit(0)
+			return
 		}
 	}
 }