Final minor updates for master release.

- Updated ShapeOko2 defaults based on machine testing of the basic
model provided by Inventables. (or close to it.) Should be pretty
conservative but much faster than before. For example, X and Y axes are
set at (10x) faster at 5000mm/min. It can run much faster than this,
but this seems like a safe speed for everyone.

- Updated README for master release.

- Added some new settings methods for clearing the EEPROM when changing
versions. Needs some more work, but it should ok for master release.
Should work on it more for the next version.

defaults.h

@@ -157,16 +157,16 @@
   #define DEFAULT_Z_STEPS_PER_MM (MICROSTEPS_Z*STEP_REVS_Z/MM_PER_REV_Z)
   #define DEFAULT_X_MAX_RATE 5000.0 // mm/min
   #define DEFAULT_Y_MAX_RATE 5000.0 // mm/min
-  #define DEFAULT_Z_MAX_RATE 750.0 // mm/min
+  #define DEFAULT_Z_MAX_RATE 500.0 // mm/min
   #define DEFAULT_X_ACCELERATION (250.0*60*60) // 25*60*60 mm/min^2 = 25 mm/sec^2
   #define DEFAULT_Y_ACCELERATION (250.0*60*60) // 25*60*60 mm/min^2 = 25 mm/sec^2
   #define DEFAULT_Z_ACCELERATION (50.0*60*60) // 25*60*60 mm/min^2 = 25 mm/sec^2
-  #define DEFAULT_X_MAX_TRAVEL 200.0 // mm
-  #define DEFAULT_Y_MAX_TRAVEL 200.0 // mm
-  #define DEFAULT_Z_MAX_TRAVEL 200.0 // mm
+  #define DEFAULT_X_MAX_TRAVEL 290.0 // mm
+  #define DEFAULT_Y_MAX_TRAVEL 290.0 // mm
+  #define DEFAULT_Z_MAX_TRAVEL 100.0 // mm
   #define DEFAULT_STEP_PULSE_MICROSECONDS 10
   #define DEFAULT_STEPPING_INVERT_MASK 0
-  #define DEFAULT_DIRECTION_INVERT_MASK ((1<<Y_AXIS)|(1<<Z_AXIS))
+  #define DEFAULT_DIRECTION_INVERT_MASK ((1<<X_AXIS)|(1<<Z_AXIS))
   #define DEFAULT_STEPPER_IDLE_LOCK_TIME 255 // msec (0-254, 255 keeps steppers enabled)
   #define DEFAULT_STATUS_REPORT_MASK ((BITFLAG_RT_STATUS_MACHINE_POSITION)|(BITFLAG_RT_STATUS_WORK_POSITION))
   #define DEFAULT_JUNCTION_DEVIATION 0.05 // mm