Had an assert fire when a message ID was reused with a different count.
It was likely because of messages crossing between two variants, but
still, fix: delete what's been saved so far when a new count shows up.
Handles case where the app receives only a subset of the SMS messages
into which a larger game-level message has been broken. Now when it
restarts and the remaining parts come in the whole can be reassembled.
And use in linux client. Goal here is to reproduce then improve the
Android SMS pre- and post-processing stuff with a common/ implementation
that can be tested on linux and used wherever.
