Added a "Reinitialize" button for mics

If the mic device starts going crazy or needs to be reset for whatever
possible reason and you don't want to restart the stream, you can now
reset the mic by using the "Reinitialize" button in audio settings next
to the mic device drop-down.  This will shut down the mic, and then
reinitialize it one second later.

Shouldn't need to be used with the newer audio code, but is provided
just in case.
Merge branch 'master' of https://github.com/jp9000/OBS