Apptentive module stubs

Not sure what the best way to deal with 3rd-party modules is, but I just threw it in a new folder.

Also, most of these methods presumably take the success/error callbacks like all Trigger methods, but I'm not calling most of them. The [apptentive module docs](https://github.com/apptentive/apptentive-trigger-io) show extra arguments, but right now their code passes objects, so I don't know what the fuck that is. Just not gonna bother with it right now.