Undirected graphs

The code was modified in https://github.com/vchilkuri/vchilkuri.github.io/blob/master/src/ccNetViz.js

/* Code for unidirectional graphs  GSoC 2017*/
var uniqObj = {};
var uniqObjArray = [];

function checkUniqIdForUnidirectional(el) {
    if (el.__uniqid !== undefined) {
        el.uniqid = el.__uniqid;
        delete el.__uniqid;
    } else if (el.uniqid === undefined) {
        var sUid = el.source.uniqid || el.source;
        var tUid = el.target.uniqid || el.target;
        if (sUid > tUid) {
            var temp = sUid;
            sUid = tUid;
            tUid = temp;
        }
        var index = sUid + ":" + tUid;
        if (!uniqObj[index]) {
            el.uniqid = ++lastUniqId;
            uniqObj[index] = el.uniqid;
            uniqObjArray.push(el);
        } else {
            el.uniqid = uniqObj[index];
        }
    }
}

/* code for unidirectional graphs ends GSoC 17 */

This method has to be developed further after adding the layout options.