bug 964877 - ensure *app* object has *receipts* property; r=mfinkle

--HG--
extra : rebase_source : 042bf6816913dd5a957f1b17b765a15fbe593698
bug 963898 - access DOMApplicationRegistry.webapps directly when autouninstalling webapp; r=mfinkle

--HG--
extra : rebase_source : f9da4d65bd026d25771978657d0cef5c3f05119b