Use a single tab field separator in keywords.txt

Each field of keywords.txt is separated by a single true tab. When you use multiple tabs it causes the field to be interpreted as empty. On Arduino IDE 1.6.5 and newer an empty KEYWORD_TOKENTYPE causes the default editor.function.style coloration to be used (as with KEYWORD2, KEYWORD3, LITERAL2). On Arduino IDE 1.6.4 and older it causes the keyword to not be recognized for any special coloration.

Reference:
https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5:-Library-specification#keywords

keywords.txt

@@ -2,36 +2,36 @@
 OpenAudio_ArduinoLibrary	KEYWORD1
 
 #data type / class / static function names
-float32_t		KEYWORD1
+float32_t	KEYWORD1
 audio_block_f32_t	KEYWORD1
-AudioStream_F32		KEYWORD1
+AudioStream_F32	KEYWORD1
 AudioConnection_F32	KEYWORD1
 
 AudioControlTLV320AIC3206	KEYWORD1
-inputSelect		KEYWORD2
+inputSelect	KEYWORD2
-setMicBias		KEYWORD2
+setMicBias	KEYWORD2
-volume			KEYWORD2
+volume	KEYWORD2
-volume_dB		KEYWORD2
+volume_dB	KEYWORD2
-setInputGain_dB		KEYWORD2
+setInputGain_dB	KEYWORD2
 
 AudioControlSGTL5000_Extended	KEYWORD1
-micBiasEnable		KEYWORD2
+micBiasEnable	KEYWORD2
 
 AudioConvert_I16toF32	KEYWORD1
 AudioConvert_F32toI16	KEYWORD1
 
 AudioEffectGain_F32	KEYWORD1
-setGain_dB		KEYWORD2
+setGain_dB	KEYWORD2
 
 AudioFilterFIR_F32	KEYWORD1
 AudioEffectIIR_F32	KEYWORD1
 AudioEffectCompressor_F32	KEYWORD1
 AudioInputI2S_F32	KEYWORD1
-AudioMemory_F32		KEYWORD1
+AudioMemory_F32	KEYWORD1
 AudioMemoryUsage_F32	KEYWORD1
 AudioMemoryUsageMax_F32	KEYWORD1
 AudioMemoryUsageMaxReset_F32	KEYWORD1
-AudioMixer4_F32		KEYWORD1
+AudioMixer4_F32	KEYWORD1
 AudioMultiply_F32	KEYWORD1
 AudioOutputI2S_F32	KEYWORD1
 AudioPlayQueue_F32	KEYWORD1
@@ -42,8 +42,8 @@ AudioSynthWaveform_F32	KEYWORD1
 
 
 AudioSynthWaveformSine_F32	KEYWORD1
-frequency		KEYWORD2
+frequency	KEYWORD2
-phase			KEYWORD2
+phase	KEYWORD2
-amplitude		KEYWORD2
+amplitude	KEYWORD2