Show Postfix queue data on a Ratex currency exchange rate display.

notes:
- Baud rate defaults to 300
- Battery holds RTC data, display data and settings.. if its dead, must be configured each time
- Serial port is basically just another way to send commands like the IR remote does
- Display row/column numbers may not match actual physical layout!
- Display has small serial buffer, so data must be rate limited
- originally made by Friend Spring Industrial Co

mq.py should be on the mail server(s)

checkqueues.sh sits on a jump host or web server

ratex.py runs on computer connected to Ratex display

ratex-time.py sets clock