Various minor updates and variable definition corrections. Removed deprecated acceleration manager.

- Removed deprecated acceleration manager (non-functional since v0.7b)
- Updated variable types and function headers. - Updated stepper
interrupt to ISR() from SIGNAL()+sei(). - General code cleanup.

protocol.c

@@ -31,10 +31,12 @@
 #include <avr/pgmspace.h>
 #define LINE_BUFFER_SIZE 50
 
-static char line[LINE_BUFFER_SIZE];
-static uint8_t char_counter;
+static char line[LINE_BUFFER_SIZE]; // Line to be executed. Zero-terminated.
+static uint8_t char_counter; // Last character counter in line variable.
+static uint8_t iscomment; // Comment/block delete flag for processor to ignore comment characters.
 
-static void status_message(int status_code) {
+static void status_message(int status_code) 
+{
   if (status_code == 0) {
     printPgmString(PSTR("ok\r\n"));
   } else {
@@ -57,12 +59,15 @@ static void status_message(int status_code) {
 
 void protocol_init() 
 {
+  char_counter = 0; // Reset line input
+  iscomment = false;
   printPgmString(PSTR("\r\nGrbl " GRBL_VERSION));
   printPgmString(PSTR("\r\n"));  
 }
 
 // Executes one line of input according to protocol
-uint8_t protocol_execute_line(char *line) {
+uint8_t protocol_execute_line(char *line) 
+{     
   if(line[0] == '$') {
     return(settings_execute_line(line)); // Delegate lines starting with '$' to the settings module
   } else {
@@ -70,15 +75,16 @@ uint8_t protocol_execute_line(char *line) {
   }
 }
 
+
+// Process one line of incoming serial data. Remove unneeded characters and capitalize.
 void protocol_process()
 {
   char c;
-  uint8_t iscomment = false;
   while((c = serial_read()) != SERIAL_NO_DATA) 
   {
-    if ((c == '\n') || (c == '\r')) { // End of block reached
+    if ((c == '\n') || (c == '\r')) { // End of line reached
       if (char_counter > 0) {// Line is complete. Then execute!
-        line[char_counter] = 0; // terminate string
+        line[char_counter] = 0; // Terminate string
         status_message(protocol_execute_line(line));
       } else { 
         // Empty or comment line. Skip block.