Move logic from tableView to Section

[MontakOleg]

This allows to create custom smart OrganicSections, for example DynamicHeightReuseOrganicSection:

- (CGFloat)cellHeightForRow:(NSInteger)row inTableView:(UITableView *)tableView
{
    if (self.reuseEnabled) {
        OrganicCell *cell = [self cellForRow:row inTableView:tableView];
        [cell layoutIfNeeded];
        return cell.height;
    }
    else {
        [super cellHeightForRow:row inTableView:tableView];
    }
}