Mostly, the inheritance graph for MessageRecord/MmsMessageRecord was
all messed up, and each class was overloaded for things it shouldn't
have been.
1) Broke MessageRecord/MmsMessageRecord up into: DisplayRecord, ThreadRecord,
MessageRecord, SmsMessageRecord, NotificationMmsMessageRecord, and
MediaMmsMessageRecord.
2) Updated all the adapters/views to keep pace with that change.