Fixed bug in Graph.prototype.merge
Fixed bug in Graph.prototype.merge

Was using 'graph' var instead of 'this'.. thanks to Nessia for reporting this.

pingjiang/springy,shigeruNakajima/springy,kidylee/springy,dabobert/springy,kidylee/springy,dabobert/springy,dhotson/springy,shigeruNakajima/springy,drstarry/springy,pingjiang/springy,tigerleapgorge/springy,tigerleapgorge/springy,dhotson/springy,mikaa123/springy