v1 Audio default device changed notification - attempt to resolve #61

[MadShadow-]

Implements the AudioDeviceChangedListener class for the win api. When the user now changes the default audio endpoint (headphones to speakers) the game will also switch to that desired output.

[MadShadow-]

One thing I didn't really take into account is how people use their audio devices. alcReopenDeviceSOFT(dev, nullptr, nullptr); will always route the output to the current default device, when a change is detected. This might not be the desired behaviour. However, I don't think the original gothic had a selection for audio endpoints.

[Try]

Implemented separately device switch, as well as "device-less" buffers as part of #61 .