Fixed tapping on the last line in more correct way

Previously it was partly fixed in https://github.com/carezone/Kal/pull/1  But it didn't cover all the cases. And now I understand that solution was'n correct. It was an attempt to fix consequences. But the real problem that `hitTest:withEvent:` [here](https://github.com/carezone/Kal/blob/3398427db3810474065600c02de72beb6f4ea40d/src/KalGridView.m#L107) and [here](https://github.com/carezone/Kal/blob/3398427db3810474065600c02de72beb6f4ea40d/src/KalGridView.m#L146) may return `KalTileView` which is not visible for a user because in this month view there are only 5 weeks. So the more correct (I think) way to fix it is to hide tile views which are not used for particular month. with such solution `hitTest:withEvent:` will not return such views.