update RtAudio to 4.0.12 and RtMidi to 2.0.1
adjust for RtMidi update
cmake: support Jack audio backend on Linux

To facilitate support for Jack, add options WITH_JACK, WITH_ALSA,
and WITH_OSS to allow individual selection of supported audio backends.
otherlibs: RtAudio3: fix building with Jack backend
marsystems: AudioSink: prototype backend selection
apps: sfplay: prototype audio backend selection