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.

settings.h

@@ -29,7 +29,7 @@
 
 
 #define GRBL_VERSION "0.9g"
-#define GRBL_VERSION_BUILD "20140813"
+#define GRBL_VERSION_BUILD "20140817"
 
 // Version of the EEPROM data. Will be used to migrate existing data from older versions of Grbl
 // when firmware is upgraded. Always stored in byte 0 of eeprom
@@ -103,6 +103,12 @@ extern settings_t settings;
 // Initialize the configuration subsystem (load settings from EEPROM)
 void settings_init();
 
+// Helper functions to clear and restore EEPROM defaults
+void settings_restore_global_settings();
+void settings_clear_parameters();
+void settings_clear_startup_line();
+void settings_clear_build_info();
+
 // A helper method to set new settings from command line
 uint8_t settings_store_global_setting(uint8_t parameter, float value);