* Regression tests for the GSM 03.38 message class behind sms.flash
* Read the GSM 03.38 message class where the spec puts it, and refuse a flash message no alphabet can carry
* Keep the code span in the message-class decision on one line
* Stop offering the flash message class as an alphabet, and check the encoding option by name
* Settle every refusable send option in one check, and record what the review left open
* Say what the flash refusal and the encoding option actually do
* Keep the README off the alphabet whose long messages do not fit
