Use correct field separator in keywords.txt

The Arduino IDE requires the use of a single true tab separator between the keyword name and identifier. When spaces are used rather than a true tab the keyword is not highlighted.

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

Author: per1234

keywords.txt

@@ -15,4 +15,4 @@ PciListenerImp	KEYWORD1
 
 PciListenerImp2	KEYWORD1
 init	KEYWORD2
-lastVal KEYWORD2
+lastVal	KEYWORD2