[patch] support for jack in libao

The patch for the configure.ac and src/plugins/Makefile.am is 0001-jack-plugin.patch

The code for the plugin itself is libao-jack-plugin.tgz

By default it connects to all available physical ports. It can be configured with the parameter "ports" ports=system:playback_1,system:playback_2

The plugin uses libsamplerate to resample the audio to the jack server rate. There are different algorithms in libsamplerate. There are selected according to the value of parameter "quality" (value from 0 to 9). The default is 5. It impacts the CPU consumption.