AppNexus: Slim down some export activity e2e tests
AppNexus: Fix line-item and campaign updates
 * Replace deprecated formatting implementation with serialized dictionary
 * Only include fields that need to be modified (don't overwrite others)
Merge branch 'master' of https://github.com/RareCrowds/OpenAdStack
AppNexus: Use embedded default ad type definitions from AppNexusActivities assembly in traveltorial e2e test