Update keywords

keywords.txt

@@ -67,6 +67,7 @@ extmem_malloc	KEYWORD2
 extmem_free	KEYWORD2
 extmem_calloc	KEYWORD2
 extmem_realloc	KEYWORD2
+strcasecmp	KEYWORD2
 
 # removed by Arduino 1.0, now also removed from Teensyduino
 #BYTE	LITERAL1