Uploaded New App Builder

I updated the App Builder tool a while back, but for some reason I never
merged it into Xplat. The new version supports background images, app
promo, and advertisement settings. It also works from within the tools
folder now rather than needing to be moved to the root.
Merge pull request #16 from winappkits/master

Merge Updates
Merge pull request #60 from acrow59/master

Uploaded New App Builder