Get all inbound and outbound links connected to the cell `model`.
function(model, opt) {

        opt = opt || {};

        if (_.isUndefined(opt.inbound) && _.isUndefined(opt.outbound)) {
            opt.inbound = opt.outbound = true;
        }

        var links = [];
        
        this.each(function(cell) {

            var source = cell.get('source');
            var target = cell.get('target');

            if (source && source.id === model.id && opt.outbound) {
                
                links.push(cell);
            }

            if (target && target.id === model.id && opt.inbound) {

                links.push(cell);
            }
        });

        return links;
    }