Added travis status icon to README
Added travis status icon to README

kristianmandrup/virtus,mallikarjunayaddala/virtus,baojjeu/virtus,artemeff/virtus,macressler/virtus,lgierth/virtus,dslh/virtus,hapiben/virtus,XescuGC/virtus,reevoo/virtus,solnic/virtus,JustMikey/virtus,faucct/virtus,nuclearsandwich/virtus