Position reporting, refactored system variables, serial print fixes, updated streaming scripts.

- Added machine position reporting to status queries. This will be
further developed with part positioning/offsets and maintaining
location upon reset.

- System variables refactored into a global struct for better
readability.

- Removed old obsolete Ruby streaming scripts. These were no longer
compatible. Updated Python streaming scripts.

- Fixed printFloat() and other printing functions.

- Decreased planner buffer back to 18 blocks and increased TX serial
buffer to 64 bytes. Need the memory space for future developments.

- Begun adding run-time modes to grbl, where block delete toggle, mm/in
reporting modes, jog modes, etc can be set during runtime. Will be
fleshed out and placed into EEPROM when everything is added.

main.c

@@ -4,8 +4,7 @@
 
   Copyright (c) 2009-2011 Simen Svale Skogsrud
   Copyright (c) 2011 Sungeun K. Jeon
-  Copyright (c) 2011 Jens Geisler
-  
+
   Grbl is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
@@ -20,11 +19,8 @@
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <avr/io.h>
-#include <avr/sleep.h>
 #include <avr/interrupt.h>
 #include <avr/pgmspace.h>
-#include <util/delay.h>
 #include "config.h"
 #include "planner.h"
 #include "nuts_bolts.h"
@@ -34,15 +30,11 @@
 #include "gcode.h"
 #include "protocol.h"
 #include "limits.h"
-
 #include "settings.h"
 #include "serial.h"
 
-#include "print.h"
-
-// Declare system global variables
-uint8_t sys_abort; // Global system abort flag
-volatile uint8_t sys_state; // Global system state variable
+// Declare system global variable structure
+system_t sys; 
 
 int main(void)
 {
@@ -50,17 +42,18 @@ int main(void)
   sei(); // Enable interrupts
   serial_init(BAUD_RATE); // Setup serial baud rate and interrupts
   st_init(); // Setup stepper pins and interrupt timers
-  sys_abort = true;   // Set abort to complete initialization
+
+  sys.abort = true;   // Set abort to complete initialization
                     
   while(1) {
   
-    // Upon a system abort, the main program will return to this loop. Once here, it is safe to 
-    // re-initialize the system. Upon startup, the system will automatically reset to finish the 
-    // initialization process.
-    if (sys_abort) {
-      // Execute system reset
-      sys_state = 0; // Reset system state
-      sys_abort = false; // Release system abort
+    // Execute system reset upon a system abort, where the main program will return to this loop.
+    // Once here, it is safe to re-initialize the system. At startup, the system will automatically
+    // reset to finish the initialization process.
+    if (sys.abort) {
+
+      // Clear all system variables
+      memset(&sys, 0, sizeof(sys));
         
       // Reset system.
       serial_reset_read_buffer(); // Clear serial read buffer
@@ -70,19 +63,14 @@ int main(void)
       gc_init(); // Set g-code parser to default state
       spindle_init();   
       limits_init();
-
-      // TODO: For now, the stepper subsystem tracks the absolute stepper position from the point
-      // of power up or hard reset. This reset is a soft reset, where the information of the current
-      // position is not lost after a system abort. This is not guaranteed to be correct, since 
-      // during an abort, the steppers can lose steps in the immediate stop. However, if a feed
-      // hold is performed before a system abort, this position should be correct. In the next few
-      // updates, this soft reset feature will be fleshed out along with the status reporting and
-      // jogging features.
-      st_reset(); // Clear stepper subsystem variables. Machine position variable is not reset.
-
-      // Print grbl initialization message
-      printPgmString(PSTR("\r\nGrbl " GRBL_VERSION));
-      printPgmString(PSTR("\r\n'$' to dump current settings\r\n"));
+      st_reset(); // Clear stepper subsystem variables.
+      
+      // Set system runtime defaults
+      // TODO: Eventual move to EEPROM from config.h when all of the new settings are worked out. 
+      // Mainly to avoid having to maintain several different versions.
+      #ifdef CYCLE_AUTO_START
+        sys.auto_start = true;
+      #endif
     }
     
     protocol_execute_runtime();