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

@@ -51,11 +51,11 @@
 # Constants (LITERAL1)
 #######################################
 
-    I2C_MS5607		LITERAL1
+    I2C_MS5607	LITERAL1
     MS5xxx_CMD_RESET	LITERAL1
     MS5xxx_CMD_ADC_READ	LITERAL1
     MS5xxx_CMD_ADC_CONV	LITERAL1
-    MS5xxx_CMD_ADC_D1	LITERAL1	
+    MS5xxx_CMD_ADC_D1	LITERAL1
     MS5xxx_CMD_ADC_D2	LITERAL1
     MS5xxx_CMD_ADC_256	LITERAL1
     MS5xxx_CMD_ADC_512	LITERAL1