[Openal] OpenAL-Soft and Changing to new device connected at runtime

[admin at ptrefall.com]

I added a local fix/hack to make new devices connected at runtime
available. Having to exit and restart the application if you forgot to
plug in the USB microphone at startup felt a little unnecessary.

Necessary changes were added to alcGetString and WinMMOpenCapture for the
requirements I had, though this certainly breaks platform independence in
Alc.c, by asking mmsystem again for num devices and iterating over those
devices before continuing.

- Trefall