Handling device disconnects

Hey,

first of all thanks for the library, its very handy.

While using it I didn't really find a way to properly handle device disconnects. I didn't find any way to get noticed, the ListenTo happily keeps running when the device is disconnected and the IsOpen also reports that the port is still open.. I feel I'm out of luck here 🙂

I don't know if this is due to the backend, I am using the rtmidi backend but I tried to switch to portmidi as well, seemingly with the same results.

In the same vein, the device list doesn't seem to get updated when a device is connected at runtime. When trying to find the MIDI port by name it doesn't get found if it was connected later. (Actually it does get found if the device is connected shortly after starting the app but not after about 30 seconds, for whatever reason).

Edit: All of this is being tested on MacOS

Thanks again, take care!