Add option to keep client in order and go to client keys

[Unknow0]

Hi,

in order to improve usability with multiple client i added a static ordering of client and hot keys to go to a client directly (or the server)

switch-keys = ["left-alt", "grave"]
goto-keys = ["left-alt", "f1"]

[[clients]]
addr = "10.10.0.1"
goto-keys = ["left-alt", "f2"]

[[clients]]
addr = "10.10.0.2"
goto-keys = ["left-atl", "f3"]

so regardless of the connection order the switch-keys will always try to go server -> 10.10.0.1 -> 10.10.0.2 -> other client (skiping unconnected client)

Regards.