this has been requested more than once now and would allow setups with multiple non-xinerama-ed heads to function.

this requires:

• the ability to define an alternate root directory (currently defaults to ~/.winswitch)
• the ability to override the location of the server socket so that the second instance launched can find the first

At the moment, if one uses "xpra upgrade" on an existing xpra session, winswitch will see that the server process it had started has now terminated and it will close the session and kill all the remaining session processes.

Options:

• detect an exit code from the xpra server which will mean "upgrade me" and re-spawn it.

This could be tricky as there are daemons involved, pipes and file descriptors, gio file watchers, etc.

• change the xpra code to exec the new process in place so we keep the same pid and this becomes transparent to winswitch

Another benefit is that all the start options would then be preserved too (password, etc) - and we could even envisage that extra options could be specified to override existing ones

these can be handled in almost exactly the same way as regular commands, we just need to look them up in either server_commands or desktop_commands.