added the Emitter functionnality

src/audio/OpenAL/Context.cpp

src/audio/OpenAL/Context.hpp

src/audio/OpenAL/Emitter.cpp

src/audio/OpenAL/Emitter.hpp

src/audio/OpenAL/Makefile.am

src/audio/OpenAL/OpenALDevice.cpp

src/audio/OpenAL/OpenALLayer.cpp

src/audio/OpenAL/OpenALLayer.hpp

src/audio/OpenAL/WavEmitter.cpp

src/audio/OpenAL/WavEmitter.hpp

src/audio/OpenAL/example04.cpp