support bundle as optional
support bundle as optional

buddhike/builder,JeroenVinke/builder,robwormald/builder,Psvensso/builder,alexandr2110pro/builder,jrauschenbusch/builder,systemjs/builder,richardTowers/builder,lookfirst/builder,richardTowers/builder,robwormald/builder,matthewbauer/builder,lookfirst/builder,whitneyit/builder,synaptek/builder,Munter/builder,matthewbauer/builder,Psvensso/builder,ahmedshuhel/builder,Munter/builder,tonytanger/builder,systemjs/builder,alexisvincent/builder,jrauschenbusch/builder,JeroenVinke/builder,tonytanger/builder,systemjs/builder,douglasduteil/builder,douglasduteil/builder,jrauschenbusch/builder,alexisvincent/builder,alexisvincent/builder,buddhike/builder,whitneyit/builder,ahmedshuhel/builder,synaptek/builder,alexandr2110pro/builder