v1.0 Beta Release.

- Tons of new stuff in this release, which is fairly stable and well
tested. However, much more is coming soon!

- Real-time parking motion with safety door. When this compile option
is enabled, an opened safety door will cause Grbl to automatically feed
hold, retract, de-energize the spindle/coolant, and parks near Z max.
After the door is closed and resume is commanded, this reverses and the
program continues as if nothing happened. This is also highly
configurable. See config.h for details.

- New spindle max and min rpm ‘$’ settings! This has been requested
often. Grbl will output 5V when commanded to turn on the spindle at its
max rpm, and 0.02V with min rpm. The voltage and the rpm range are
linear to each other. This should help users tweak their settings to
get close to true rpm’s.

- If the new max rpm ‘$’ setting is set = 0 or less than min rpm, the
spindle speed PWM pin will act like a regular on/off spindle enable
pin. On pin D11.

- BEWARE: Your old EEPROM settings will be wiped! The new spindle rpm
settings require a new settings version, so Grbl will automatically
wipe and restore the EEPROM with the new defaults.

- Control pin can now be inverted individually with a
CONTROL_INVERT_MASK in the cpu_map header file. Not typical for users
to need this, but handy to have.

- Fixed bug when Grbl receive too many characters in a line and
overflows. Previously it would respond with an error per overflow
character and another acknowledge upon an EOL character. This broke the
streaming protocol. Now fixed to only respond with an error after an
EOL character.

- Fixed a bug with the safety door during an ALARM mode. You now can’t
home or unlock the axes until the safety door has been closed. This is
for safety reasons (obviously.)

- Tweaked some the Mega2560 cpu_map settings . Increased segment buffer
size and fixed the spindle PWM settings to output at a higher PWM
frequency.

- Generalized the delay function used by G4 delay for use by parking
motion. Allows non-blocking status reports and real-time control during
re-energizing of the spindle and coolant.

- Added spindle rpm max and min defaults to default.h files.

- Added a new print float for rpm values.

grbl/print.h

@@ -46,11 +46,11 @@ void printFloat(float n, uint8_t decimal_places);
 //  - CoordValue: Handles all position or coordinate values in inches or mm reporting.
 //  - RateValue: Handles feed rate and current velocity in inches or mm reporting.
 //  - SettingValue: Handles all floating point settings values (always in mm.)
+//  - RPMValue: Handles spindle RPM values in settings and reports.
 void printFloat_CoordValue(float n);
-
 void printFloat_RateValue(float n);
-
 void printFloat_SettingValue(float n);
+void printFloat_RPMValue(float n);
 
 // Debug tool to print free memory in bytes at the called point. Not used otherwise.
 void printFreeMemory();