Updates to edge/dev. Line buffer increased/planner buffer decreased. Line overflow feedback.

- Increased g-code parser line buffer to 70 characters (from 50) to
prevent some long arc commands from getting truncated.

- Decreased planner buffer from 18 to 17 blocks to free up memory for
line buffer.

- Added a line buffer overflow feedback error (Thanks @BHSPitMonkey!)

config.h

@@ -210,7 +210,7 @@
 // available RAM, like when re-compiling for a Mega or Sanguino. Or decrease if the Arduino
 // begins to crash due to the lack of available RAM or if the CPU is having trouble keeping
 // up with planning new incoming motions as they are executed. 
-// #define BLOCK_BUFFER_SIZE 18  // Uncomment to override default in planner.h.
+// #define BLOCK_BUFFER_SIZE 17  // Uncomment to override default in planner.h.
 
 // Line buffer size from the serial input stream to be executed. Also, governs the size of 
 // each of the startup blocks, as they are each stored as a string of this size. Make sure
@@ -220,7 +220,7 @@
 // can be too small and g-code blocks can get truncated. Officially, the g-code standards 
 // support up to 256 characters. In future versions, this default will be increased, when 
 // we know how much extra memory space we can re-invest into this.
-// #define LINE_BUFFER_SIZE 50  // Uncomment to override default in protocol.h
+// #define LINE_BUFFER_SIZE 70  // Uncomment to override default in protocol.h
   
 // Serial send and receive buffer size. The receive buffer is often used as another streaming
 // buffer to store incoming blocks to be processed by Grbl when its ready. Most streaming