1) Allow imports from the stock SMS database at any time.
2) Provide plaintext export support, in a format compatible with
the "SMS Backup And Restore" app.
3) Fix the DB weirdness on encrypted restore that previously
required killing the app.
Android design pattern best practice recommends placing the settings
menu item below all other items because it's not frequently needed.
In that spirit, I've also moved the clear passphrase option to be first
since it is likely to be used more often than database import/export.
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
1) Start breaking the UI out into Fragments.
2) Switch to Cursor loaders from managed cursors.
3) Switch to inflated menu resources.
4) Break out some basic functionality into helper classes.
