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

@@ -17,7 +17,7 @@ click	KEYWORD2
 move	KEYWORD2
 press	KEYWORD2
 release	KEYWORD2
-isPressed KEYWORD2
+isPressed	KEYWORD2
 
 #######################################
 # Constants (LITERAL1)