Add: check permit index path

[bannzai]

Why

I get out of bounds from Shoyu.Section func rowFor(row: Int) via UITableViewDelegate.didEndDisplayCell.
I faced this problem when I write that swift logic.

    class AnyTableViewController: UITableViewController {

        var elements: Element = // Elements ...

        func setupShoyu() {
        tableView.source = Source().createSection { section in
            section.createRows(elements) { row in
                ...
            }
        }



        func deleteElement(element: Element) { 
            elements.removeFrom(element) 
            setupShoyu() // Reset source.
            tableView.reloadData()  // Get out of bounds from this statement.
        }
    }

I thought removeElement and reset source then disappear corresponded cell.
But Shoyu.Section.rows.count is less than the past.
When get Shoyu.Section.row[indexPath.row], it would fall down.

What

I add Shoyu.Source.isPermitIndexPath function.
This function is check indexPath when didEndDisplayCell.
If not permit indexPath when early stage return.

[xai3]

👍 thx!