audout:u OpenAudioOut and IAudioOut (#138)

* Updated the audout:u and IAudioOut, now it might work with RetroArch without trigger an assert, however it's not the ideal implementation

* Updated the audout:u and IAudioOut, now it might work with RetroArch without trigger an assert, however it's not the ideal implementation

* audout:u OpenAudioOut implementation and IAudioOut cmd 1,2,3,4,5 implementation

* using an enum for audio_out_state as well as changing its initialize to member initializer list

* Minor fixes, added Service_Audio for LOG_*, changed PcmFormat enum to EnumClass

* Minor fixes, added Service_Audio for LOG_*, changed PcmFormat enum to EnumClass

* added missing Audio loggin subclass, minor fixes, clang comment breakline

* Solving backend logging conflict

* minor fix

* Fixed duplicated Service NVDRV in backend.cpp, my bad

src/common/logging/backend.cpp

@@ -39,6 +39,7 @@ namespace Log {
     SUB(Service, DSP)                                                                              \
     SUB(Service, HID)                                                                              \
     SUB(Service, NVDRV)                                                                            \
+    SUB(Service, Audio)                                                                            \
     CLS(HW)                                                                                        \
     SUB(HW, Memory)                                                                                \
     SUB(HW, LCD)                                                                                   \