1) Add configuration options for APN information in TextSecure settings.
2) Fall back to TextSecure settings if system settings are unavailable
while sending/receiving MMS.
3) Catch sqlite exception when devices randomly don't have the same
APN db or table structure.
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.
1) Change all instances which use concatenation to build strings
with variables in them to use string formatting instead.
2) Extract all string literals from layouts and menus into strings.xml
3) Extract all string literals from code into strings.xml
