Xpra: Ticket #122: drop compatibility for versions without the "raw_packets" feature (pre 0.3.x)

Follow up from #68, this will allow us to simplify the code greatly:

Mon, 23 Jul 2012 17:05:48 GMT - Antoine Martin:

done in r1166

We cannot drop all of it from the read loop though because old clients still send the initial packet in the old format. This can be removed at a later date.

Mon, 23 Jul 2012 17:12:45 GMT - Antoine Martin: status changed; resolution set

Sat, 23 Jan 2021 04:46:08 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/122