Fix scroll regression introduced in 562ac8f

Simply checking that the Buttons bitset of both events is the same is
not enough to set the motion to true. We have to make ture that the
event is only for buttons and not for the mouseweel.

application.go

@@ -134,7 +134,8 @@ func (app *Application) Start() error {
 					redraw = app.root.OnPasteEvent(customEvt)
 				}
 			case *tcell.EventMouse:
-				hasMotion := app.prevMouseEvt.Buttons() == event.Buttons()
+				onlyButtons := event.Buttons() < tcell.WheelUp
+				hasMotion := onlyButtons && app.prevMouseEvt.Buttons() == event.Buttons()
 				customEvt := customMouseEvent{event, hasMotion}
 				app.prevMouseEvt = event
 				redraw = app.root.OnMouseEvent(customEvt)