title: How to determine if Dropbox has been installed on iOS device?
body: <p>My app uses Dropbox to allow users to make backups of their core data store. Is there a way to determine programmatically if the Dropbox app has been installed, so I can prompt users to set up the backup? I don't want to bug users who don't use Dropbox, but I want to try to get as many users to use backups as possible.</p>