Implement experimental DTR handshake

[derekolson]

I'm attempting to implement the hardware handshake in #27 based on the arduino printer library. However, I'm having issues getting it to work correctly. Any pointers would be appreciated!

[paulhayes]

Hi @derekolson Did you make an progress on this?

[paulhayes]

It seems it might be possible to do this directly on the serial interface by enabling flow control rather than through the python script using GPIO.

https://github.com/mholling/rpirtscts

[derekolson]

@paulhayes apologies for the extreme delay on this... but I got this working for a project awhile back. If you were still interested its in a branch here: https://github.com/derekolson/Python-Thermal-Printer/tree/dtr-handshake

[paulhayes]

Fab, thanks @derekolson!