tintColor support for icon

Enables something like that: 

        UIImage *feedImage = [[UIImage imageNamed:@"icon-tab-feed"] imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
        
        cell.firstLeftAction = [PDGestureTableViewCellAction
                                 actionWithIcon:feedImage
                                 color:[UIColor colorWithRed:0/255.0f green:156/255.0f blue:20/255.0f alpha:1.0f]
                                 fraction:0.25
                                 didTriggerBlock:^(PDGestureTableView *gestureTableView, NSIndexPath*indexPath) {
                                     [this handleSwipeDelete:indexPath];
                                     [gestureTableView pushAndDeleteCellForIndexPath:indexPath completion:^{
                                         [this updateZeroInboxVisibility];
                                    
                                     }];
                                 }];
        
        cell.firstLeftAction.iconTintColor = [UIColor whiteColor];