Fixed shared build info code.

- The build info options of “two switches on an axis” and “homing init
lock” shared the same letter ‘L’. The former is now ’T’.

grbl/grbl.h

@@ -23,7 +23,7 @@
 
 // Grbl versioning system
 #define GRBL_VERSION "1.1f"
-#define GRBL_VERSION_BUILD "20170223"
+#define GRBL_VERSION_BUILD "20170227"
 
 // Define standard libraries used by Grbl.
 #include <avr/io.h>

grbl/report.c

@@ -395,7 +395,7 @@ void report_build_info(char *line)
     serial_write('H');
   #endif
   #ifdef LIMITS_TWO_SWITCHES_ON_AXES
-    serial_write('L');
+    serial_write('T');
   #endif
   #ifdef ALLOW_FEED_OVERRIDE_DURING_PROBE_CYCLES
     serial_write('A');