chore(travis): Force Travis to use npm v2
chore(travis): Force Travis to use npm v2

Versions before 2 have race conditions that can cause false negatives in our tests

vanessayuenn/batarang,hitesh97/batarang,angular/batarang,jbnicolai/batarang,hitesh97/batarang,angular/batarang,iegik/batarang,jvilk/angularjs-batarang,iegik/batarang,DrewML/batarang,DrewML/batarang,angular/batarang,jvilk/angularjs-batarang,jvilk/angularjs-batarang,iegik/batarang,vanessayuenn/batarang,DrewML/batarang,vanessayuenn/batarang,jbnicolai/batarang,seawenzhu/batarang,jbnicolai/batarang,hitesh97/batarang,seawenzhu/batarang,seawenzhu/batarang