Brightkite has released an update to its social networking app for the iPhone and iPod touch, adding iOS 4 support and several other enhancements. Brightkite 2.8 now provides native iOS 4 support including Fast App Switching and background posting and photo uploads. The new version also allows users to view badges that they or their friends have earned and limit notifications on friends’ checkins to only when they are nearby. New high-resolution…