Swift 4.2 support with did select and deselect delegate methods

Going forwards the library will support Swift 4.2 support.
There's also a new did select and deselect delegate method:

    /// Fired when a cell is selected.
    ///
    /// - Parameters:
    ///   - dataTable: SwiftDataTable
    ///   - indexPath: the index path of the row selected
    @objc optional func didSelectItem(_ dataTable: SwiftDataTable, indexPath: IndexPath)

    /// Fired when a cell has been deselected
    ///
    /// - Parameters:
    ///   - dataTable: SwiftDataTable
    ///   - indexPath: the index path of the row deselected
    @objc optional func didDeselectItem(_ dataTable: SwiftDataTable, indexPath: IndexPath)