Xpra: Ticket #2749: remote-logging : from server to client

To make it easier to debug servers (see also #2750), when the server log file may not be easily accessible.

Log both to log file and clients when requested:

xpra start --remote-logging=both

And then the clients can then do:

xpra attach --remote-logging=receive [--windows=no --speaker=no --notifications=no]

To receive the server's log output.

Sun, 03 May 2020 03:37:06 GMT - Antoine Martin: status, version, description changed

Sat, 09 May 2020 05:34:10 GMT - Antoine Martin: priority changed

Could be very useful for debugging, raising.

Fri, 15 May 2020 15:33:10 GMT - Antoine Martin: description changed

Done in r26355.

Still TODO:

Tue, 19 May 2020 15:09:28 GMT - Antoine Martin: status changed; resolution set

Tested OK on win32.

Minor tweaks and man page updates in r26415.

Sat, 23 Jan 2021 05:59:43 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/2749