Freeze to working version of PCK Pod
Add spec method for creating response data
Messages have a disposition property
App better handles fetching data on startup

- Models expect updated JSON from server responses
- Current user conforms to NSCoding
- AppDelegate archives/unarchives current user
- Don't crash if we have credentials, but no data archive

Sorry for the large commit
Display refresh indicator when refreshing messages
Set localized information correctly on 500 error
Handle rare error case

User has credentials, but no saved data, and the network request fails.
Create separate protocol for VC user auth success
User can retry after rare error case
Updated build number to 18