Add keywords

keywords.txt

 Audio	KEYWORD2
 AudioConnection	KEYWORD2
 AudioInputI2S	KEYWORD2
+AudioInputI2Sslave	KEYWORD2
 AudioOutputI2S	KEYWORD2
+AudioOutputI2Sslave	KEYWORD2
 AudioOutputSPDIF	KEYWORD2
 AudioOutputPWM	KEYWORD2
 AudioControlSGTL5000	KEYWORD2
+AudioControlWM8731	KEYWORD2
+AudioControlWM8731master	KEYWORD2
 AudioMemory	KEYWORD2
 
 AudioAnalyzeFFT256	KEYWORD2
 enhanceBassDisable	KEYWORD2
 surroundSound	KEYWORD2
 surroundSoundEnable	KEYWORD2
+surroundSoundDisable	KEYWORD2
 calcBiquad	KEYWORD2
 sampleRate	KEYWORD2
 bits	KEYWORD2
+mute_PCM	KEYWORD2
 
 AudioMemoryUsage	KEYWORD2
 AudioMemoryUsageMax	KEYWORD2
 FILTER_LOSHELF	LITERAL1
 FILTER_HISHELF	LITERAL1
 
+FLAT_FREQUENCY	LITERAL1
+PARAMETRIC_EQUALIZER	LITERAL1
+TONE_CONTROLS	LITERAL1
+GRAPHIC_EQUALIZER	LITERAL1
+
 WAVEFORM_SINE	LITERAL1
 WAVEFORM_SAWTOOTH	LITERAL1
 WAVEFORM_SQUARE	LITERAL1

output_spdif.h

 	static DMAChannel dma;
 	static void isr(void);
 private:
-    static uint32_t vucp;
+	static uint32_t vucp;
 	static audio_block_t *block_left_2nd;
 	static audio_block_t *block_right_2nd;
 	static uint16_t block_left_offset;