Added Gulp asset manifest change detection for non-bundled asset groups.
Added Gulp asset manifest change detection for non-bundled asset groups.

When running the 'build' task, a non-bundled asset group will now be rebuilt if the asset manifest file itself is newer than any of the output files.

LaserSrl/Orchard,IDeliverable/Orchard,aaronamm/Orchard,Dolphinsimon/Orchard,IDeliverable/Orchard,gcsuk/Orchard,omidnasri/Orchard,Fogolan/OrchardForWork,Dolphinsimon/Orchard,jimasp/Orchard,Fogolan/OrchardForWork,Lombiq/Orchard,hbulzy/Orchard,IDeliverable/Orchard,LaserSrl/Orchard,jersiovic/Orchard,omidnasri/Orchard,Dolphinsimon/Orchard,OrchardCMS/Orchard,fassetar/Orchard,OrchardCMS/Orchard,omidnasri/Orchard,jersiovic/Orchard,Dolphinsimon/Orchard,jersiovic/Orchard,Lombiq/Orchard,gcsuk/Orchard,jersiovic/Orchard,LaserSrl/Orchard,hbulzy/Orchard,omidnasri/Orchard,fassetar/Orchard,IDeliverable/Orchard,IDeliverable/Orchard,jimasp/Orchard,fassetar/Orchard,hbulzy/Orchard,yersans/Orchard,Lombiq/Orchard,Fogolan/OrchardForWork,LaserSrl/Orchard,omidnasri/Orchard,gcsuk/Orchard,jimasp/Orchard,yersans/Orchard,fassetar/Orchard,aaronamm/Orchard,aaronamm/Orchard,OrchardCMS/Orchard,Dolphinsimon/Orchard,jimasp/Orchard,yersans/Orchard,OrchardCMS/Orchard,omidnasri/Orchard,LaserSrl/Orchard,jersiovic/Orchard,omidnasri/Orchard,omidnasri/Orchard,gcsuk/Orchard,omidnasri/Orchard,hbulzy/Orchard,jimasp/Orchard,aaronamm/Orchard,OrchardCMS/Orchard,yersans/Orchard,Lombiq/Orchard,aaronamm/Orchard,Fogolan/OrchardForWork,yersans/Orchard,fassetar/Orchard,Fogolan/OrchardForWork,gcsuk/Orchard,Lombiq/Orchard,hbulzy/Orchard