v1.1e: New laser features. G-code parser refactoring. CoreXY homing fix.

- Increment to v1.1e due to new laser features.

- After several discussions with some prominent laser people, a few
tweaks to the new laser mode has been installed.

- LASER: M3 behaves in a constant power mode.

- LASER: M4 behaves in a dynamic power mode, where the laser power is
automatically adjusted based on how fast Grbl is moving relative to the
programmed feed rate. This is the same as the  CONSTANT_POWER_PER_RATE
config.h option in the last version. NOTE: When not in motion in M4,
Grbl automatically turns off the laser. Again, it only operates while
moving!

- LASER: Only G1, G2, and G3 motion modes will turn on the laser. So,
this means that G0, G80 motion modes will always keep the laser
disabled. No matter if M3/M4 are active!

- LASER: A spindle stop override is automatically invoked when a laser
is put in a feed hold. This behavior may be disabled by a config.h
option.

- Lots of little tweaks to the g-code parser to help streamline it a
bit. It should no effect how it operates. Generally just added a parser
flag to track and execute certain scenarios a little more clearly.

- Jog motions now allow line numbers to be passed to it and will be
displayed in the status reports.

- Fixed a CoreXY homing bug.

- Fixed an issue when $13 is changed, WCO isn’t sent immediately.

- Altered how spindle PWM is set in the stepper ISR. Updated on a step
segment basis now. May need to change this back if there are any
oddities from doing this.

- Updated some documentation. Clarified why M0 no longer showing up in
$G and why a `1.` floating point values are shown with no decimals,
like so `1`.

grbl/config.h

@@ -569,12 +569,12 @@
 #define PARKING_PULLOUT_RATE 100.0 // Pull-out/plunge slow feed rate in mm/min.
 #define PARKING_PULLOUT_INCREMENT 5.0 // Spindle pull-out and plunge distance in mm. Incremental distance.
                                       // Must be positive value or equal to zero.
-        
-// Experimental feature that adjusts laser power (PWM output) based on current running speed of the
-// machine. When laser mode is enabled, Grbl will turn off the spindle PWM pin whenever it is not 
-// moving, which may be confusing to some users to why their laser is not on. This behavior may change
-// in future iterations of this feature, where it will turn on to the minimum rpm value when active.
-// #define LASER_CONSTANT_POWER_PER_RATE
+
+// This option will automatically disable the laser during a feed hold by invoking a spindle stop
+// override immediately after coming to a stop. However, this also means that the laser still may
+// be reenabled by disabling the spindle stop override, if needed. This is purely a safety feature
+// to ensure the laser doesn't inadvertently remain powered while at a stop and cause a fire.
+#define DISABLE_LASER_DURING_HOLD // Default enabled. Comment to disable.
 
 /* ---------------------------------------------------------------------------------------
    OEM Single File Configuration Option