Fixed issue with M3 laser state changes and coincident targets.

[fix] When in M3 constant laser power mode, a change from G0 to G1
would not set the laser on, if G1 was passed with a coincident target.
Motion controller now checks for a coincident target situation and will
force a spindle sync when detected.

doc/log/commit_log_v1.1.txt

@@ -1,3 +1,16 @@
+----------------
+Date: 2017-01-31
+Author: Sonny Jeon
+Subject: Additional build info in the $I printout.
+
+- [new] Added total available planner buffer blocks (15 shown, but
+there are 16. one is used by the ring buffer and to execute system
+motions) and serial RX buffer bytes. This information is useful for
+GUIs to setup and optimize their streaming protocols easily.
+
+[doc] Updated the interface document to reflect the change.
+
+
 ----------------
 Date: 2017-01-29
 Author: Sonny Jeon

grbl/grbl.h

@@ -23,7 +23,7 @@
 
 // Grbl versioning system
 #define GRBL_VERSION "1.1f"
-#define GRBL_VERSION_BUILD "20170131"
+#define GRBL_VERSION_BUILD "20170223"
 
 // Define standard libraries used by Grbl.
 #include <avr/io.h>

grbl/motion_control.c

@@ -65,8 +65,12 @@ void mc_line(float *target, plan_line_data_t *pl_data)
   } while (1);
 
   // Plan and queue motion into planner buffer
-  // uint8_t plan_status; // Not used in normal operation.
-  plan_buffer_line(target, pl_data);
+  if (plan_buffer_line(target, pl_data) == PLAN_EMPTY_BLOCK) {
+    if (bit_istrue(settings.flags,BITFLAG_LASER_MODE)) {
+      // Correctly set laser state, if there is a coincident position passed. Forces a buffer sync.
+      spindle_sync((pl_data->condition & (PL_COND_FLAG_SPINDLE_CW|PL_COND_FLAG_SPINDLE_CCW)), pl_data->spindle_speed);
+    }
+  }
 }