Handle ALSA input/output clients with the same name

[scottyeager]

Currently we fail in this specific case where both input and output clients have the same name:

ALSA_DESIRED_CONNECTIONS = [
    ("apc:apc", "APC MINI:APC MINI MIDI 1"),
    ("APC MINI:APC MINI MIDI 1", "apc:apc")
]

This fixes it:

ALSA_DESIRED_CONNECTIONS = [
    ("132:apc", "APC MINI:APC MINI MIDI 1"),
    ("APC MINI:APC MINI MIDI 1", "131:apc")
]

But that's not a real solution, since the device numbers can change.

Note that in this case APC MINI is a single device with dual capabilities, while apc is two different devices: one input and one output.

Since the ports have different capabilities but the same name, we should be able to distinguish them. Assuming our pairs are written ("source", "sink") then there's no ambiguity. If two input or two output clients have the same name, we can't do much about that though.

This isn't fatal since we control the enough of the names to be able to workaround, but it can be more robust.