Initialization and Plug-in loading infrastructure. The classes provided here are used to load available plug-ins (AudioFileReader, AudioFileWriter, FormatConversionProvider, MixerProvider, MidiDeviceProvider, MidiFileReader, MidiFileWriter, SoundbankReader) and maintain lists of them. These classes are needed by Tritonus only if it is used as a stand-alone Java Sound implementation. They are called by AudioSystem and MidiSystem.