feat: update keybinding to quit Viddy

    * 'q' will quit viddy, only if it's not in help view, else it'll
      go back
    * 'Q` to exit viddy from any view

viddy.go

@@ -553,11 +553,27 @@ func (v *Viddy) Run() error {
 			any = true
 		}
 
-		if event.Key() == tcell.KeyEsc || event.Rune() == 'q' {
+		if event.Key() == tcell.KeyEsc {
 			v.showHelpView = false
 			v.arrange()
 		}
 
+		if event.Rune() == 'q' {
+			if (v.showHelpView) {  // if it's help mode, just go back
+				v.showHelpView = false
+				v.arrange()
+			} else {  // it's not help view, so just quit
+				v.app.Stop()
+				os.Exit(0)
+			}
+		}
+
+		// quit viddy from any view
+		if event.Rune() == 'Q' {
+			v.app.Stop()
+			os.Exit(0)
+		}
+
 		switch event.Rune() {
 		case 's':
 			v.isSuspend = !v.isSuspend